Complejos de paladio (II) con carbenos mesoiónicos (MICs) diversidad estructural y catálisis homogénea

Una nueva serie de mono- y bis-1,2,3-triazol-5-ilidenos de paladio(ii) conteniendo (MICs) han sido sintetizados, aislados y caracterizados. La introducción de paladio a sales de 1,2,3-triazolio mediante su reacción con Pd(OAc)₂ generó complejos bimetálicos del tipo [Pd(MIC)I₂]₂con puentes del tipo ( ₂-I₂)y también complejos monometálicos con estructuras generales [PdMIC₂I₂ como mezclas isoméricascis y trans. Adicionalmente, se realizó la síntesis selectiva de complejos tipo-PEPPSI [MIC(PdI₂)Py] mediante la reacción de las sales de triazolio con PdCl₂ y K₂CO₃ en piridina. Todos los compuestos han sido caracterizados mediante RMN de ¹H y ¹ᶾC, FT-IR y cristalografía de rayos-X de monocristal. Estudios catalíticos preliminares de los nuevos complejos en procesos de formación de enlaces C-C y C-N serán discutidos.A new series of mono- and bis-1,2,3-triazol-5-ylidene (MIC) palladium(ii) complexes have been synthesized, isolated and characterized. Palladation of N3-methylated phenoxy derived 1,2,3-triazolium salts withPd(OAc)₂,afforded ₂-I₂ bridged bimetallic [Pd(MIC)I₂]₂and monometallic biscarbene complexes PdMIC₂I₂as a mixture of cis- and trans isomers. Efficient synthesis of PEPPSI-type complexes [Py(PdI₂)MIC] was achieved by the treatment of the triazolium precursors with PdCl₂in pyridine. All the complexes have been fully characterized by ¹H and ¹ᶾC NMR, FT-IR and single crystal X-ray diffraction. Preliminary catalytic performances of the new complexes in C-C and C-N bond forming processes will be discussed

Genomic and proteomic analyses of Mycobacterium bovis BCG Mexico 1931 reveal a diverse immunogenic repertoire against tuberculosis infection

<p>Abstract</p> <p>Background</p> <p>Studies of <it>Mycobacterium bovis </it>BCG strains used in different countries and vaccination programs show clear variations in the genomes and immune protective properties of BCG strains. The aim of this study was to characterise the genomic and immune proteomic profile of the BCG 1931 strain used in Mexico.</p> <p>Results</p> <p>BCG Mexico 1931 has a circular chromosome of 4,350,386 bp with a G+C content and numbers of genes and pseudogenes similar to those of BCG Tokyo and BCG Pasteur. BCG Mexico 1931 lacks Region of Difference 1 (RD1), RD2 and N-RD18 and one copy of IS6110, indicating that BCG Mexico 1931 belongs to DU2 group IV within the BCG vaccine genealogy. In addition, this strain contains three new RDs, which are 53 (RDMex01), 655 (RDMex02) and 2,847 bp (REDMex03) long, and 55 single-nucleotide polymorphisms representing non-synonymous mutations compared to BCG Pasteur and BCG Tokyo. In a comparative proteomic analysis, the BCG Mexico 1931, Danish, Phipps and Tokyo strains showed 812, 794, 791 and 701 protein spots, respectively. The same analysis showed that BCG Mexico 1931 shares 62% of its protein spots with the BCG Danish strain, 61% with the BCG Phipps strain and only 48% with the BCG Tokyo strain. Thirty-nine reactive spots were detected in BCG Mexico 1931 using sera from subjects with active tuberculosis infections and positive tuberculin skin tests.</p> <p>Conclusions</p> <p>BCG Mexico 1931 has a smaller genome than the BCG Pasteur and BCG Tokyo strains. Two specific deletions in BCG Mexico 1931 are described (RDMex02 and RDMex03). The loss of RDMex02 (<it>fadD23</it>) is associated with enhanced macrophage binding and RDMex03 contains genes that may be involved in regulatory pathways. We also describe new antigenic proteins for the first time.</p

Análisis fitoquímico: una herramienta para develar el potencial biológico y farmacológico de las plantas

The phytochemical sieve is a tool in the investigation of the biological and pharmacological potential that plants possess. In this paper we describe the way in which the study of the chemical compounds present in the plants can be carried out from the identification of the specific chemical groups for each bioactive molecule; special emphasis is placed on the phytochemical sieve and on the structures and generalities of a chemical group of biological interest.El tamiz fitoquímico es una herramienta en la investigación del potencial biológico y farmacológico que poseen las plantas. En este trabajo se describe la forma en que se puede llevar a cabo el estudio de los compuestos químicos presentes en las plantas a partir de la identificación de los grupos químicos específicos para cada molécula bioactiva; se hace especial énfasis en el tamiz fitoquímico y en las estructuras y generalidades de grupo químico de interés biológico

Kinetic Study of Fungal Growth of Several Tanninolytic Strains Using Coffee Pulp Procyanidins

Procyanidins are bioactive molecules with industrial and pharmaceutical relevance, they are present in recalcitrant agro-industrial wastes that are difficult to degrade. In this study, we evaluated the potential consumption of procyanidins from Aspergillus niger and Trichoderma harzianum strains in submerged fermentations. For this purpose, a culture medium containing salts, glucose, and procyanidins was formulated, where procyanidins were added to the medium after the near-total consumption of glucose. The submerged cultures were carried out in amber flasks at 30 &deg;C and 120 rpm. The addition of procyanidins to the culture medium increased the formation of micellar biomass for all the strains used. The use of glucose affected the growth of A. niger GH1 and A. niger HS1, however, in these assays, a total consumption of procyanidins was obtained. These results show that the consumption of procyanidins by fungal strains in submerged fermentations was influenced by the pH, the use of glucose as the first source of carbon, and the delayed addition of procyanidins to the medium. The study showed that A. niger and T. harzianum strains can be used as a natural strategy for the consumption or removal of procyanidins present in recalcitrant residues of risk to the environment and human health

Kinetic Study of Fungal Growth of Several Tanninolytic Strains Using Coffee Pulp Procyanidins

Procyanidins are bioactive molecules with industrial and pharmaceutical relevance, they are present in recalcitrant agro-industrial wastes that are difficult to degrade. In this study, we evaluated the potential consumption of procyanidins from Aspergillus niger and Trichoderma harzianum strains in submerged fermentations. For this purpose, a culture medium containing salts, glucose, and procyanidins was formulated, where procyanidins were added to the medium after the near-total consumption of glucose. The submerged cultures were carried out in amber flasks at 30 °C and 120 rpm. The addition of procyanidins to the culture medium increased the formation of micellar biomass for all the strains used. The use of glucose affected the growth of A. niger GH1 and A. niger HS1, however, in these assays, a total consumption of procyanidins was obtained. These results show that the consumption of procyanidins by fungal strains in submerged fermentations was influenced by the pH, the use of glucose as the first source of carbon, and the delayed addition of procyanidins to the medium. The study showed that A. niger and T. harzianum strains can be used as a natural strategy for the consumption or removal of procyanidins present in recalcitrant residues of risk to the environment and human health

Phenoxy-Linked Mesoionic Triazol-5-ylidenes as Platforms for Multinuclear Transition Metal Complexes

The preparation and full characterization of a variety of mono- ([<b>L1</b>-H]), di- ([<b>L2</b>-H₂], [<b>L2A</b>-H2]), and tri- ([<b>L3</b>-H₃]) 1,2,3-triazolium salts constructed form “clicked” hydroxybenzene derivatives are reported. Deprotonation with potassium hexamethyldisilazide, followed by <i>in situ</i> metalation, allowed for the synthesis of a series of mono- (<b>L1</b>·[M]), di- (<b>L2</b>·[M]₂, <b>L2</b>·[M]₂), and trinuclear (<b>L3</b>·[M]₃) group 9–11 (M = [Rh­(CO)₂Cl], [Pd­(allyl)­Cl], and [AuCl]) triazol-5-ylidene metal complexes. In solution, all metal complexes feature symmetrical patterns displaying <i>C</i>₂ and <i>C</i>₃ fold axes when supported by di- and tritriazol-5-ylidene ligands. The vibration frequencies of <b>Ln</b>·[Rh­(CO)₂Cl]_<i>n</i> (<i>n</i> = 1–3) complexes indicate that the electron-donor properties of the new ligands are comparable to those for previously reported MIC complexes and superior to classical NHCs. Prompting coordination of the vicinal phenoxy group to the metal centers proved unsuccessful after treatment of the <b>Ln</b>·[Rh­(CO)₂Cl]_<i>n</i> and <b>Ln</b>·[Pd­(allyl)­Cl]_<i>n</i> (<i>n</i> = 1–3) precursors with AgBF₄; the expected chelated cationic complexes were highly unstable, indicating a weak or no coordination availability through the oxygen atom. Crystal structures of the complexes <b>L1</b>·[AuI] and <b>L2A</b>·[Pd­(allyl)­I]₂ illustrated the metal center geometrical environment and confirmed the lack of coordination through the phenoxy moiety of the ligand. Preliminary catalytic trials established the enhanced performance of di- and trimetallic palladium complexes in cross-coupling reactions and the intramolecular cyclization of enynes catalyzed by gold complexes

Phenoxy-Linked Mesoionic Triazol-5-ylidenes as Platforms for Multinuclear Transition Metal Complexes

The preparation and full characterization of a variety of mono- ([<b>L1</b>-H]), di- ([<b>L2</b>-H₂], [<b>L2A</b>-H2]), and tri- ([<b>L3</b>-H₃]) 1,2,3-triazolium salts constructed form “clicked” hydroxybenzene derivatives are reported. Deprotonation with potassium hexamethyldisilazide, followed by <i>in situ</i> metalation, allowed for the synthesis of a series of mono- (<b>L1</b>·[M]), di- (<b>L2</b>·[M]₂, <b>L2</b>·[M]₂), and trinuclear (<b>L3</b>·[M]₃) group 9–11 (M = [Rh­(CO)₂Cl], [Pd­(allyl)­Cl], and [AuCl]) triazol-5-ylidene metal complexes. In solution, all metal complexes feature symmetrical patterns displaying <i>C</i>₂ and <i>C</i>₃ fold axes when supported by di- and tritriazol-5-ylidene ligands. The vibration frequencies of <b>Ln</b>·[Rh­(CO)₂Cl]_<i>n</i> (<i>n</i> = 1–3) complexes indicate that the electron-donor properties of the new ligands are comparable to those for previously reported MIC complexes and superior to classical NHCs. Prompting coordination of the vicinal phenoxy group to the metal centers proved unsuccessful after treatment of the <b>Ln</b>·[Rh­(CO)₂Cl]_<i>n</i> and <b>Ln</b>·[Pd­(allyl)­Cl]_<i>n</i> (<i>n</i> = 1–3) precursors with AgBF₄; the expected chelated cationic complexes were highly unstable, indicating a weak or no coordination availability through the oxygen atom. Crystal structures of the complexes <b>L1</b>·[AuI] and <b>L2A</b>·[Pd­(allyl)­I]₂ illustrated the metal center geometrical environment and confirmed the lack of coordination through the phenoxy moiety of the ligand. Preliminary catalytic trials established the enhanced performance of di- and trimetallic palladium complexes in cross-coupling reactions and the intramolecular cyclization of enynes catalyzed by gold complexes

Atypical Cristae Morphology of Human Syncytiotrophoblast Mitochondria: ROLE FOR COMPLEX V*

Mitochondrial complexes I, III2, and IV from human cytotrophoblast and syncytiotrophoblast associate to form supercomplexes or respirasomes, with the following stoichiometries: I1:(III2)1 and I1:(III2)1–2:IV1–4. The content of respirasomes was similar in both cell types after isolating mitochondria. However, syncytiotrophoblast mitochondria possess low levels of dimeric complex V and do not have orthodox cristae morphology. In contrast, cytotrophoblast mitochondria show normal cristae morphology and a higher content of ATP synthase dimer. Consistent with the dimerizing role of the ATPase inhibitory protein (IF1) (García, J. J., Morales-Ríos, E., Cortés-Hernandez, P., and Rodríguez-Zavala, J. S. (2006) Biochemistry 45, 12695–12703), higher relative amounts of IF1 were observed in cytotrophoblast when compared with syncytiotrophoblast mitochondria. Therefore, there is a correlation between dimerization of complex V, IF1 expression, and the morphology of mitochondrial cristae in human placental mitochondria. The possible relationship between cristae architecture and the physiological function of the syncytiotrophoblast mitochondria is discussed