New Pd–Fe ferrocenyl antiparasitic compounds with bioactive 8-hydroxyquinoline ligands: a comparative study with their Pt–Fe analogues†]]> In the search for a more effective chemotherapy for the treatment of Human African Trypanosomiasis, a disease caused by the parasite Trypanosoma brucei, the development of ferrocenyl compounds has arisen as a promising strategy. In this work, five new Pd–Fe heterobimetallic [PdII(L)(dppf)](PF6) compounds, including 8-hydroxyquinolyl derivatives HL1–HL5 as bioactive ligands and dppf = 1,1’-bis(diphenylphosphino)
ferrocene as the organometallic co-ligand, were synthesized and fully characterized in the solid state and in solution. Molecular structures of three compounds were solved by single crystal X-ray diffraction methods. The compounds displayed submicromolar or micromolar IC50 values against bloodstream
T. brucei (IC50: 0.33–1.2 μM), and good selectivity towards the pathogen (SI: 4–102) with respect to mammalian macrophages (cell line J774). The new Pd complexes proved to be 2-fold to 45-fold more potent than the drug nifurtimox but most of them are less active than their Pt analogues. Potential molecular
targets were studied. The complexes interact with DNA but they do not alter the intracellular thiolredox homeostasis of the parasite. In order to understand and predict the main structural determinants on the anti-T. brucei activity, a search of quantitative structure–activity relationships (QSAR) was performed including all the [M(L)(dppf)](PF6) complexes, where M = Pd(II) or Pt(II), currently and previously
developed by us. The correlation obtained shows the relevance of the electronic effects, the lipophilicity and the type of metal. According to the QSAR study, compounds with electron-withdrawing ligands, higher lipophilicity and harboring Pt would result in higher T. brucei cytotoxicity. From the whole series of
[M(L)(dppf)](PF6) compounds developed, where M = Pt(II) or Pd(II) and HL = 8-hydroxyquinolyl derivatives, Pt-dppf-L4 (IC50 = 0.14 μM, SI = 48) was selected to perform an exploratory pre-clinical study in infected mice. This hit compound lacks acute toxicity when applied to animals in the dose/regimen described and exerts an anti-proliferative effect on parasites, which extends animal survival but is not curative.

]]> Rivas, Feriannys]]> Medeiros, Andrea]]> Quiroga, Cristina]]> Benítez, Diego]]> Comini, Marcelo]]> Rodríguez Arce, Esteban]]> Machado, Ignacio]]> Cerecetto, Hugo]]> Gambino, Dinorah]]> Royal Society of Chemistry]]> Información sobre Derechos de Autor

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La legislación uruguaya protege el derecho de autor sobre toda creación literaria, científica o artística, tanto en lo que tiene que ver con sus derechos morales, como en lo referente a los derechos patrimoniales con sujeción a lo establecido por el derecho común y las siguientes leyes (LEY 9.739 DE 17 DE DICIEMBRE DE 1937 SOBRE PROPIEDAD LITERARIA Y ARTISTICA CON LAS MODIFICACIONES INTRODUCIDAS POR LA LEY DE DERECHO DE AUTOR Y DERECHOS CONEXOS No. 17.616 DE 10 DE ENERO DE 2003, LEY 17.805 DE 26 DE AGOSTO DE 2004, LEY 18.046 DE 24 DE OCTUBRE DE 2006)

ADVERTENCIA - La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.

]]> 10.1039/d0dt03963b ]]> Application of pillared raw clay-base catalysts and natural solar radiation for water decontamination by the photo-Fenton process]]> This study presents a novel application of the heterogeneous solar photo-Fenton process using an iron-pillared clay (Fe-PILC) as a photocatalyst under natural sunlight. The Fe-PILC is characterized by thermogravimetric analysis, EDXRF, SEM and nitrogen adsorption–desorption isotherms. The solar photo-reactor consists of a tubular borosilicate tube with a compound parabolic collector (CPC) and two different materials as reflective material for performance comparison. Phenol is used as model pollutant. The catalytic tests are monitored by the
concentration of the pollutant, intermediates and the iron leaching, as well as the accumulated energy during the reaction time. Complementary catalytic tests allowed to establish the influence of parallel processes that could contribute to phenol removal. Experimental data proved that the Fe-PILC is active as heterogenous catalyst in photo-Fenton like processes promoted by natural solar radiation. The catalyst showed good stability in the process and allowed a 99%+ removal of the pollutant and its intermediates. Fenton, photolysis and adsorption do not contribute significantly to phenol removal. Finally, when comparing different reflective materials in the CPC, the aluminium sheet proved to be more efficient than the polyester film metallized with aluminium.

]]> Rodríguez, Mayra]]> Bussi, Juan]]> De León, María Andrea]]> Información sobre Derechos de Autor

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]]> 10.1016/j.seppur.2020.118167 ]]> From chain- to graphene-like hydroxyl-terminated (ZnO)n clusters with n≤6 obtained via zinc dimethoxide Hydrolysis and Condensation: ab initio structural, electronic, vibrational and optical properties calculations ]]> Recent reports are focusing on the structural evolution from the
atomic-scale and also at the expenses of alkyl zinc alkoxide
precursors towards (ZnO)n clusters and nanostructures with
different interesting motifs, but still not much is known about
their electronic properties. In this manuscript, we present a
theoretical study using DFT and TD-DFT methodologies on the
hydrolysis and condensation of zinc dimethoxide precursor in
its monomeric, dimeric and trimeric forms towards thermodynamically stable hydroxyl-terminated (ZnO)n clusters with novel chain- and graphene-like fashions. For all cases, distinct vibrational and optical spectra features were assigned evidencing a global monotonic decrease in the opto-electronic gap with increasing oligomerization and cyclization stages. In addition, the electron-affinity of all clusters was also observed to be enhanced with increasing oligomerization and cyclization
stages and the electronic charge localization in -e charged
clusters was observed to be strongly related to the presence of
zinc-oxo subunits and other particular structural features. Our
calculations also indicate that the stabilization through hydroxyl
termination of both chain- and graphene-like ZnO clusters not
only could be a promising driving force to obtain larger atomicscale 1D and 2D nanostructures but also envisage interesting properties, particularly as electronic acceptor materials for energy applications.

]]> Romero, Mariano]]> Mombrú, Dominique]]> Pignanelli, Fernando]]> Faccio, Ricardo]]> Mombrú, Álvaro W.]]> Editorial Union of Chemical Societies]]> Información sobre Derechos de Autor

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]]> 10.1002/cphc.202100054 ]]> When a tritrophic interaction goes wrong to the third level: xanthoxylin from trees causes the honeybee larval mortality in colonies affected by the river disease]]> The “River Disease” (RD), a disorder impacting honeybee colonies located close to waterways with abundant riparian
vegetation (including Sebastiania schottiana, Euphorbiaceae), kills newly hatched larvae. Forager bees from RD-affected
colonies collect honeydew excretions from Epormenis cestri (Hemiptera: Flatidae), a planthopper feeding on trees of S.
schottiana. First-instar honeybee larvae fed with this honeydew died. Thus, we postulated that the nectars of RD-affected
colonies had a natural toxin coming from either E. cestri or S. schottiana. An untargeted metabolomics characterization of
fresh nectars extracts from colonies with and without RD allowed to pinpoint xanthoxylin as one of the chemicals present in higher amounts in nectar from RD-affected colonies than in nectars from healthy colonies. Besides, xanthoxylin was also
found in the aerial parts of S. schottiana and the honeydew excreted by E. cestri feeding on this tree. A larva feeding assay
where xanthoxylin-enriched diets were offered to 1st
instar larvae showed that larvae died in the same proportion as larvae did when offered enriched diets with nectars from RD-colonies. These findings demonstrate that a xenobiotic can mimic the RD syndrome in honeybee larvae and provide evidence of an interspecific flow of xanthoxylin among three trophic levels. Further, our results give information that can be considered when implementing measures to control this honeybee disease.

]]> Rossini, Carmen]]> Almeida, Lucía]]> Arredondo, Daniela]]> Antúnez, Karina]]> Santos, Estela]]> Rodríguez Haralambides, Alejandra]]> Invernizzi, Ciro]]> Información sobre Derechos de Autor

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]]> 10.1007/s10886-021-01296-5 ]]> Debaryomyces hansenii F39A as biosorbent for textiledye removal]]> Ruscasso, Florencia]]> Bezus, Brenda]]> Garmendi, Gabriela]]> Vero, Silvana]]> Curutchet, Gustavo]]> Cavello, Ivana]]> Cavalitto, Sebastián]]> Información sobre Derechos de Autor

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]]> 10.1016/j.ram.2020.10.004 ]]> Inhibition of inflammatory cytokine production and proliferation in macrophages by Kunitz-type inhibitors from Echinococcus granulosus]]> The genus Echinococcus of cestode parasites includes important pathogens of humans and livestock animals.
Transcriptomic and genomic studies on E. granulosus and E. multilocularis uncovered striking expansion of monodomain Kunitz proteins. This expansion is accompanied by the specialization of some family members away from the ancestral protease inhibition function to fulfill cation channel blockade functions. Since cation channels are involved in immune processes, we tested the effects on macrophage physiology of two E. granulosus Kunitztype inhibitors of voltage-activated cation channels (Kv) that are close paralogs. Both inhibitors, EgKU-1 and EgKU-4, inhibited production of the Th1/Th17 cytokine subunit IL-12/23p40 by macrophages stimulated with
the TLR4 agonist LPS. In addition, EgKU-4 but not EgKU-1 inhibited production of the inflammatory cytokine IL-
6. These activities were not displayed by EgKU-3, a family member that is a protease inhibitor without known
activity on cation channels. EgKU-4 potently inhibited macrophage proliferation in response to M-CSF, whereas EgKU-1 displayed similar activity but with much lower potency, similar to EgKU-3. We discuss structural differences, including a heavily cationic C-terminal extension present in EgKU-4 but not in EgKU-1, that may explain the differential activities of the two close paralogs.

]]> Sagasti, Camila]]> Casaravilla, Cecilia]]> Fernández, Cecilia]]> Fló, Martín]]> Díaz, Alvaro]]> (Por favor lea este aviso antes de abrir los documentos u objetos)

]]> 10.1016/j.molbiopara.2021.111351 ]]> Isomerization and fragmentation reactions on the [C2SH4] potential energy surface: the metastable thione S-Methylide isomer.]]> Thione S-methylide, parent species of the thiocarbonyl ylide family, is a 1,3-dipolar species on the [C2SH4] potential energy surface, not so much studied as its isomers, thiirane, vinyl thiol, and thioacetaldehyde. The conrotatory ring-closure reaction toward thiirane was studied in the 90s, but no complete analysis of the potential energy surface is available. In this paper, we report a computational study of the reaction scheme linking all species. We employed several computational methods (density functional theory, CCSD(T) composite schemes, and CASSCF/CASPT2 multireference procedures) to find the best description of thione S-methylide, its isomers, and transition states. The barrier from thiirane to thione Smethylide amounts to 52.2 kcal mol−1 (against 17.6 kcal mol−1 for the direct one), explaining why thiocarbonyl ylides cannot be prepared from thiiranes. Conversion of thiirane to vinyl thiol implies a large barrier, supporting why the reaction has been observed only at high temperatures.
Fragmentations of thiirane to S(3P) or S(1D) and ethylene as well as decomposition to hydrogen sulfide plus acetylene were also explored. Triplet and singlet open-shell species were identified as intermediates in the fragmentations, with energies lower than the transition state between thiirane and vinyl thiol, explaining the preference of the latter at low temperatures.

]]> Salta, Zoe]]> Segovia, Marcos E.]]> Katz, Aline]]> Tasinato, Nicola]]> Barone, Vincenzo]]> Ventura, Oscar N.]]> American Chemical Society]]> Información sobre Derechos de Autor

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]]> 10.1021/acs.joc.0c02835 ]]> Materiales microporosos basados en tierras raras con potencial aplicación en dispositivos electrónicos]]> QUIMICA INORGANICA

]]> os polímeros de coordinación metal-orgánicos (MOFs) son un tipo de material poroso sumamente versátil en cuanto al rango de aplicaciones posibles. Los MOFs se forman a partir del ensamblaje entre centros metálicos y ligandos orgánicos en una red tridimensional. Las propiedades del MOF en cuestión
dependen del centro metálico, el ligando, el tipo de conexión, la estructura tridimensional, la morfología, entre otros factores. La inmensidad de posibles arreglos ha permitido la utilización de
MOFs en diversos campos de aplicación, desde la adsorción y separación de gases, hasta la fotocatálisis. Siendo los MOFs materiales de elevada cristalinidad, la resolución de sus estructuras por métodos de difracción es accesible, lo que permite aspirar a comprender las bases de su funcionamiento en término de arreglos atómicos. Este trabajo tratará de explorar dos aplicaciones en particular y sus relaciones con la estructura atómica para una familia de MOFs: la conducción protónica para potenciales electrolitos de celdas de combustible de baja temperatura y la generación de un material emisor de luz blanca a partir de tres centros lantánidos emisores.
La tesis se centra en el estudio de una familia de MOFs heteropolinucleares de fórmula general [Ln2M3(oda)6]∙nH2O, formados a partir de un metal lantánido trivalente (Ln3+), un metal de transición divalente (M2+) y el ligando oxidiacetato (oda2-). El ensamblaje entre los tres lleva en general a la
formación de una estructura hexagonal neutra o de una red cúbica aniónica con contraiones intercalados en los poros del material. Se estudiaron principalmente las series que estaban
prácticamente inexploradas de M = Ni y Co, en todo el rango de iones Ln. Se focalizó en los aspectos estructurales de los compuestos, sobre todo en las características geométricas que llevan a la obtención de un polimorfo preferencial en función de los metales M y Ln. Se propuso un modelo en el cual se define un factor de tolerancia en función de los radios iónicos de los metales, con el objetivo de explicar y predecir el tipo de estructura esperada. Se puso a prueba el factor definido frente a un sistema binario en la posición M: [Yb2NixCo3-x(oda)6]∙nH2O. Se caracterizaron por medio de difracción
de polvo diferentes muestras con distinto grado de sustitución.

]]> Igoa Saldaña, Fernando]]> Torres, Julia (Directora de tesis)]]> Suescun, Leopoldo (Director de tesis)]]> Información sobre Derechos de Autor

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La legislación uruguaya protege el derechode autor sobre toda creación literaria, científica o artística, tanto en lo que tiene que ver con sus derechos morales, como en lo referente a los derechos patrimoniales con sujeción a lo establecido por el derecho común y las siguientes leyes (LEY 9.739 DE 17 DE DICIEMBRE DE 1937 SOBRE PROPIEDAD LITERARIA Y ARTISTICA CON LAS MODIFICACIONES INTRODUCIDAS POR LA LEY DE DERECHO DE AUTOR Y DERECHOS CONEXOS No. 17.616 DE 10 DE ENERO DE 2003, LEY 17.805 DE 26 DE AGOSTO DE 2004, LEY 18.046 DE 24 DE OCTUBRE DE 2006 LEY 18.046 DE 24 DE OCTUBRE DE 2006)

]]> Souza, Rodrigo]]> Fernández, Paula]]> Muela, Agustina]]> Cesio, María Verónica]]> Heinzen, Horacio]]> Pareja, Lucia]]> Información sobre Derechos de Autor

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.1007/s12161-020-01953-7 ]]> Light modulates important physiological features of Ralstonia pseudosolanacearum during the colonization of tomato plants]]> Ralstonia pseudosolanacearum GMI1000 (Rpso GMI1000) is a soil-borne vascular phytopathogen that infects host plants through the root system causing wilting disease in a wide range of agroeconomic interest crops, producing economical losses. Several features contribute to the full bacterial virulence. In this work we study the participation of light, an important environmental factor, in the regulation of the physiological attributes and infectivity of Rpso GMI1000. In silico analysis of the Rpso genome revealed the presence of a Rsp0254 gene, which encodes a putative blue light LOV-type photoreceptor. We constructed a mutant strain of Rpso lacking the LOV protein and found that the loss of this protein and light, influenced characteristics involved in the pathogenicity process such as
motility, adhesion and the biofilms development, which allows the successful host plant colonization, rendering bacterial wilt. This protein could be involved in the adaptive responses to environmental changes. We demonstrated that light sensing and the LOV protein, would be used as a location signal in the host plant, to regulate the expression of several virulence factors, in a time and tissue dependent way. Consequently, bacteria could use an external signal and Rpsolov gene to know their location within plant tissue during the colonization process.

]]> Tano, Josefina]]> Ripa, María Belén]]> Tondo, María Laura]]> Carrau, Analía]]> Petrocelli, Silvana]]> Rodriguez, María Victoria]]> Ferreira, Virgnia]]> Siri, María Inés]]> Piskulic, Laura]]> Orellano, Elena Graciela]]> Información sobre Derechos de Autor

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Objetivo: Aislar e identificar rizobacterias de J. curcas con actividad antagónica frente a hongos fitopatógenos (Curvularia lunata y Fusarium equiseti) del cultivo y evaluar la capacidad de estas para promover el crecimiento de plantas de jitomate.

Materiales y métodos: Las cepas bacterianas se obtuvieron por dilución en serie. La actividad antagónica se evaluó mediante compuestos volátiles y difusibles en medio de cultivo PDA; además, se determinó la producción de compuestos antifúngicos y metabolitos que promueven el crecimiento de plantas. Las cepas se identificaron mediante la amplificación de los genes ARNr 16S y sodA; posteriormente, se inocularon en semillas de jitomate para evaluar la germinación de las plantas y la promoción del crecimiento.

Resultados y discusión: Las bacterias antagonistas se identificaron como Bacillus mojavensis, Bacillus subtilis, Bacillus thuringiensis y Pseudomonas aeruginosa. El efecto antifúngico sobre el crecimiento micelial de C. lunata y F. equiseti se debió a la presencia de compuestos volátiles y difusibles con inhibición de entre 30 % y 79 %. Pseudomonas aeruginosa mostró el efecto inhibitorio más fuerte (48.7 a 79.8 %). Bacillus subtilis (A1), B. mojavensis (A4) y B. thuringiensis (A6, A8) mostraron la mayor germinación (70 % a 88 %). El crecimiento de las plantas de jitomate tratadas con cepas bacterianas fue significativamente mayor (P < 0.05) que el de las plantas testigo.

Conclusión: Ocho aislados de rizobacterias de J. curcas mostraron actividad antagónica frente a C. lunata y F. equiseti, y demostraron su capacidad para mejorar la germinación y promover el crecimiento de las plantas de jitomate.

]]> Toledo Hernández, Erubiel]]> Peña Chora, Guadalupe]]> Toribio Jiménez, Jeiry]]> Romero Ramírez, Yanet]]> Bolaños Dircio, Alejandro]]> Velázquez del Valle, Miguel G.]]> Hernández Lauzardo, Ana N.]]> León Rodríguez, Renato]]> Vero, Silvana]]> Información sobre Derechos de Autor

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]]> Torres, Martín]]> de los Santos, Carolina]]> Portugau, Patrice]]> Yeste, María del Pilar]]> Castiglioni, Jorge]]> Información sobre Derechos de Autor

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]]> Maagdenberg, Hedy]]> Oosterom, Natanja]]> Zanen, Jolanda]]> Gemmati, Donato]]> Windsor, Rachael E.]]> Heil, Sandra G.]]> Esperón, Patricia]]> Jabeen, Shakila]]> Ruiz Argüelles, Guillermo J.]]> Zolk, Oliver]]> Hoerning, Susanne]]> Sleurs, Charlotte]]> López López, Elixabet]]> Moreno Galván, Mónica]]> van den Heuvel Eibrink, Marry M.]]> Maitland van der Zee, Anke H.]]> Carleton, Bruce C.]]> Información sobre Derechos de Autor

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.1016/j.critrevonc.2021.103312]]> Tunable and sizeable band gaps in strained SiC3/hBN vdW heterostructures: a potential replacement for graphene in future nanoelectronics]]> In this work, we perform first-principles density functional theory calculations to study siligraphene (SiC3)/ hexagonal boron nitride (hBN) vdW-heterostructures. Siligraphene has comparable electronic properties to graphene, including the presence of a Dirac-like cone, thus we investigate its potential as a replacement for graphene. We find that, when internal strains induced by the high lattice mismatch between the SiC3 and hBN layers are reduced, a very small and non-tunable gap is induced in a hybrid bilayer heterostructure. However, the
picture becomes quite different when structures with higher internal strains are considered. In this scenario, the
compressive strain induces a buckling in the SiC3 sheet, resulting in larger band gaps. Additionally, in many configurations, the gaps are found to be quite tunable by the application of external strains or an electrical field. Such tunability is absent in graphene/hBN heterostructures, thus giving SiC3/hBN heterostructures a clear edge. The origin of this gap and its tunability are discussed in terms of the buckling in the SiC3 layer and the interlayer charge transfer. Finally, the optical properties of these heterostructures were also investigated. Strong absorption peaks in both visible and deep UV regions were found, which could be explored for applications in future optoelectronic devices.

]]> Ullah, Saif]]> Denis, Pablo A.]]> Menezes, Marcos G.]]> Sato, Fernando]]> Información sobre Derechos de Autor

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]]> NiLaM (M = Ce and/or Zr) mixed oxide catalysts for synthesis gas production by biogas reforming processes]]> NiLaM (M = Ce and/or Zr) catalysts were prepared by the polymerized complex method and evaluated in the dry, oxidative dry, and tri-reforming of a synthetic biogas (CH4/CO2 = 1.5) at 800° C and atmospheric pressure. The catalysts that possessed the highest number of total basic sites and stronger Ni-support
interaction showed better activity and coke resistance. A lower level of carbon deposits, with higher reactivity, was found for these catalysts in tri-reforming experiments. However, catalyst deactivation was observed for NiLaCe, attributed to nickel re-oxidation.

]]> Veiga, Santiago]]> Faccio, Ricardo]]> Romero, Mariano]]> Bussi, Juan]]> Información sobre Derechos de Autor

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]]> Ventura, Oscar N.]]> Kieninger, Martina]]> Katz, Aline]]> Vega Teijido, Mauricio]]> Segovia, Marc]]> Irving, Kenneth]]> Información sobre Derechos de Autor

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]]> CATA (check-all-that-apply) questions enjoy high popularity for sensory product characterization with consumers. Amidst extensive methodological characterization, the meaning of term citation frequency has received modest attention only,
possibly hindering further uptake. The present research performed a more detailed exploration of the relationship between CATA responses and perceived intensity of sensory attributes. In addition, the following question was addressed:
How many consumers are necessary to interpret differences in CATA citation proportions as a proxy of differences in perceived intensity? The present research includes new empirical data from four consumer studies conducted in New Zealand and China under central location test conditions and a re-analysis of
one consumer study. When dealing with samples with clear differences, the percentage of consumers selecting a sensory term for describing samples tended to be linearly correlated to average intensity ratings. A median of 15 consumers was
needed for CATA to show good linear correlations with average intensity ratings, and the minimum number of consumers needed to reach the threshold for a good correlation was generally lower than 30.

]]> Vidal, Leticia]]> Ares, Gastón]]> Jaeger, Sara R.]]> Información sobre Derechos de Autor

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.1111/joss.12695 ]]> A new procedure for thioester deprotection using thioglycolic acid in both homogeneous and heterogeneous phase]]> Classic acetyl thioester protection/deprotection methodologies are widely used in organic synthesis, but deprotection step usually requires harsh conditions not suitable for labile substrates. In this work, a new method for thioester deprotection using a thiotransesterification approach is described. Firstly, thioglycolic acid (TGA) was identified as a good deprotecting reagent in solution. In order to develop a thiol polymer-supported reagent, TGA was anchored to a PEG-based resin through an amide bond (TG-NCOSH).
Both homogeneous and heterogeneous approaches were conveniently carried out at room temperature, in aqueous buffer at pH 8. The mild conditions were suitable for alkyl and phenyl thioesters. Moreover labile thioesters containing thiazolidine and oxazolidine scaffolds, bearing amine, ester and
acetal functionalities were also deprotected. The polymer-supported TGA gave better deprotection yields compared to TGA in solution, yields ranging from 61 to 90%. The feasibility of the recovery and reuse of TG-NCO-SH reagent was explored, showing it can be reused at least five times without lossing the
activity.

]]> Villamil, Valentina]]> Saiz, Cecilia]]> Mahler, Graciela]]> Información sobre Derechos de Autor

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.1016/j.tet.2021.132335 ]]> Crystal structure and magnetic study of the complex salt [RuCp(PTA)2–l-CN-1jC:2jN–RuCp(PTA)2]- [Re(NO)Br4(EtOH)0.5(MeOH)0.5] /]]> A new RuII–ReII complex salt, -cyanido-2C:N-bis[(5-cyclopentadienyl)bis- (3,5,7 triazaphosphaadamantane -P)ruthenium(II)]tetrabromido(ethanol/methanol-O)nitrosylrhenate(II), [Ru(CN)(C5H5)2(C6H12N3P)4][ReBr4(NO)-
(CH4O)0.5(C2H6O)0.5] or [RuCp(PTA)2–-CN–1C:22N-RuCp(PTA)2]-[Re(NO)Br4(EtOH)0.5(MeOH)0.5] (PTA = 3,5,7-triazaphosphaadamantane) was obtained and characterized by single-crystal X-ray diffraction, elemental analysis and infrared spectroscopy. The title salt was obtained by liquid–liquid
diffusion of methanol/DMSO solutions of (NBu4)[Re(NO)Br4(EtOH)] and[(PTA)2CpRu–-CN–1C:22N-RuCp(PTA)2](CF3SO3). The RuII and ReII independent moieties correspond to a binuclear and mononuclear complex ion, respectively. A deep geometrical parameter analysis was performed, and no significant differences were found with earlier reports containing similar molecules. The magnetic properties were investigated in the temperature range 2.0–300 K, and the complex behaves as a quasi-magnetically isolated spin doublet with weak antiferromagnetic interactions.

]]> Pacheco, Mario]]> Alvarez, Natalia]]> Cuevas, Alicia]]> Romerosa, Antonio]]> Lloret, Francesc]]> Kremer, Carlos]]> International Union of Crystallography

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> Expanding the chemical space of aryloxynaphthoquinones as potential anti-chagasic agents: synthesis and trypanosomicidal activity ]]> In continuation our effort to research the chemical space of aryloxy-naphthoquinones as potential anti-Chagas agents, we synthesized nine derivatives and these compounds were evaluated in vitro against the epimastigote and trypomastigote forms of Mexican strains of Trypanosoma cruzi (T. cruzi). Most of these derivatives are highly active against epimastigote forms (IC50 < 1.0 μM) compared to the reference drug benznidazole (Bzn). Then these were evaluated on trypomastigotes, which is showing better potency results than Bzn for compounds 3b and 3g. In addition, the cytotoxicity of these compounds was determined on the murine macrophage cell line J774. 3b and 3i were the most selective compounds
against NINOA trypomastigote and INC-5 epimastigote forms, respectively. Further these compounds also have good oral bioavailability according to theoretical predictions. Finally, we were able to determine optimal substitution patterns using pharmacophoric models. All these results are provided very useful structural information to continue our designing of naphthoquinone derivatives against T. cruzi.

]]> Becerra, Nohemí A.]]> Espinosa Bustos, Christian]]> Vázquez, Karina]]> Rivera, Gildardo]]> Paulino, Margot]]> Cantero, Jorge]]> Nogueda, Benjamín]]> Chacón Vargas, Fabiola]]> Castillo Velazquez, Uziel]]> Elizondo Rodríguez, Ana F.]]> Toledo, Sofía]]> Moreno Rodríguez, Adriana]]> Aranda, Mario]]> Salas, Cristian Osvaldo]]> Información sobre Derechos de Autor

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.1007/s00044-021-02809-3]]> A multiscale approach to predict the binding mode of metallo beta-lactamase inhibitors]]> Antibiotic resistance is a major threat to global public health. β-lactamases, which catalyze breakdown of β-lactam antibiotics, are a principal cause. Metallo β-lactamases (MBLs) represent a particular challenge because they hydrolyze almost all β-lactams and to date no MBL inhibitor has been approved for clinical use. Molecular simulations can aid drug discovery, for example, predicting inhibitor complexes, but empirical
molecular mechanics (MM) methods often perform poorly for metalloproteins. Here we present a multiscale approach to model thiol inhibitor binding to IMP-1, a clinically important MBL containing two catalytic zinc ions, and predict the binding
mode of a 2-mercaptomethyl thiazolidine (MMTZ) inhibitor. Inhibitors were first docked into the IMP-1 active site, testing different docking programs and scoring functions on multiple crystal structures. Complexes were then subjected to molecular
dynamics (MD) simulations and subsequently refined through QM/MM optimization with a density functional theory (DFT) method, B3LYP/6-31G(d), increasing the accuracy of the method with successive steps. This workflow was tested on two IMP-1: MMTZ complexes, for which it reproduced crystallographically observed binding, and applied to predict the binding mode of a third MMTZ inhibitor for which a complex
structure was crystallographically intractable. We also tested a 12-6-4 nonbonded interaction model in MD simulations and optimization with a SCC-DFTB QM/MM approach. The results show the limitations of empirical models for treating these systems and indicate the need for higher level calculations, for example, DFT/MM, for reliable structural predictions. This study demonstrates a reliable computational pipeline that can be applied to inhibitor design for MBLs and other zinc-metalloenzyme systems.

]]> Gervasoni, Silvia]]> Spencer, James]]> Hinchliffe, Philip]]> Pedretti, Alessandro]]> Vairoletti, Franco]]> Mahler, Graciela]]> Mulholland, Adrian J.

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.1002/prot.26227]]> Fe(III)-Complex-Imprinted polymers for the green oxidative degradation of the methyl orange dye pollutant]]> One of the biggest problems worldwide is the pollution of natural water bodies by dyes coming from effluents used in the textile industry. In the quest for novel effluent treatment alternatives, the aim of this work was to immobilize Fe(III) complexes in molecularly imprinted polymers (MIPs) to produce efficient Fenton-like heterogeneous catalysts for the green oxidative degradation of the methyl orange (MO) dye pollutant. Different metal complexes bearing commercial and low-cost
ligands were assayed and their catalytic activity levels towards the discoloration of MO by H2O2 were assessed. The best candidates were Fe(III)-BMPA (BMPA = di-(2-picolyl)amine) and Fe(III)-NTP (NTP = 3,30,3”-nitrilotripropionic acid), displaying above 70% MO degradation in 3 h. Fe(III)-BMPA
caused the oxidative degradation through two first-order stages, related to the formation of BMPAFe- OOH and the generation of reactive oxygen species. Only the first of these stages was detected for Fe(III)-NTP. Both complexes were then employed to imprint catalytic cavities into MIPs. The polymers showed catalytic profiles that were highly dependent on the crosslinking agent employed, with N,N-methylenebisacrylamide (MBAA) being the crosslinker that rendered polymers with optimal oxidative performance (>95% conversion). The obtained ion-imprinted polymers constitute cheap and robust solid matrices, with the potential to be coupled to dye-containing effluent treatment systems with synchronous H2O2 injection.

]]> Haller, Paulina]]> Machado, Ignacio]]> Torres, Julia]]> Vila, Agustina]]> Veiga, Nicolás]]> Información sobre Derechos de Autor

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ADVERTENCIA: La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.]]> 10.3390/polym13183127]]> 2-Mercaptomethyl thiazolidines (MMTZs) inhibit all Metallo-β- lactamase classes by maintaining a conserved binding mode]]> Metallo-β-lactamase (MBL) production in Gram-negative
bacteria is an important contributor to β-lactam antibiotic
resistance. Combining β-lactams with β-lactamase inhibitors (BLIs) is a validated route to overcoming resistance, but MBL inhibitors are not available in the clinic. On the basis of zinc utilization and sequence, MBLs are divided into three subclasses, B1, B2, and B3, whose differing active-site architectures hinder development of BLIs capable of “crossclass” MBL inhibition. We previously described 2-mercaptomethyl thiazolidines (MMTZs) as B1 MBL inhibitors (e.g., NDM-1) and here show that inhibition extends to the clinically relevant B2 (Sfh-I) and B3 (L1) enzymes. MMTZs inhibit purified MBLs in vitro (e.g., Sfh-I, Ki 0.16 μM) and potentiate β-lactam activity against producer strains. X-ray crystallography reveals that inhibition involves direct
interaction of the MMTZ thiol with the mono- or dizinc centers of Sfh-I/L1, respectively. This is further enhanced by sulfur-π
interactions with a conserved active site tryptophan. Computational studies reveal that the stereochemistry at chiral centers is critical, showing less potent MMTZ stereoisomers (up to 800-fold) as unable to replicate sulfur-π interactions in Sfh-I, largely through steric constraints in a compact active site. Furthermore, in silico replacement of the thiazolidine sulfur with oxygen (forming an oxazolidine) resulted in less favorable aromatic interactions with B2 MBLs, though the effect is less than that previously observed for the subclass B1 enzyme NDM-1. In the B3 enzyme L1, these effects are offset by additional MMTZ interactions with the protein main chain. MMTZs can therefore inhibit all MBL classes by maintaining conserved binding modes through different routes.

]]> Hinchliffe, Philip]]> Moreno, Diego M.]]> Rossi, Maria Agustina]]> Mojica, Maria F.]]> Martinez, Veronica]]> Villamil, Valentina]]> Spellberg, Brad]]> Drusano, George L.]]> Banchio, Claudia]]> Mahler, Graciela]]> Bonomo, Robert A.]]> Vila, Alejandro J.]]> Spencer, James]]> Información sobre Derechos de Autor

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