Gold trifluoromethyl complexes as efficient regioselective catalysts in alkyne hydration.

Gold (III) complexes containing trifluromethyl ligands are efficient catalyst in the hydration of alkynes, operating at low catalyst loadings, without additives, using environmentally friendly solvents and at mild conditions (60 ºC). Hydration of terminal and internal alkynes provide the corresponding ketones in quantitative yields without special precautions as dry solvents or inert atmospheres. Remarkably, hydration of asymmetric internal alkynes proceeds with moderate to notable regioselectivities, providing mixtures of the two possible isomers with ratios up to 90:10.

Melanoma mucoso de la cavidad oral: Reporte de caso

El melanoma mucoso (MM) es un subtipo raro de malignidad que surge de la transformación maligna de los melanocitos. EL MM representa el 1% de todos los casos de melanoma, siendo un subtipo agresivo y con mal pronóstico, con supervivencia global a 5 años de 10-20%. El Melanoma mucoso de la cavidad oral corresponde al 0.5% de todos los tumores malignos en la cavidad oral y al 25% de los melanomas mucosos ubicados en cabeza y cuello. Tiene una distribución anatómica de predominio en el tracto sinunasal 70%, cavidad oral 20% y otras ubicaciones como larige y faringe. Algunos probables factores de riesgo descritos son: trauma mecánico crónico, etilismo, tabaquismo, formaldehído, Sin embargo su etiología permanece incierta. Presentamos el caso de una paciente Femenina de 77 años tratada exitosamente mediante maxilectomía inferior y disección selectiva cervical izquierda. (provisto por Infomedic International)

Mucosal melanoma (MM) is a rare subtype of malignancy arising from malignant transformation of melanocytes. MM accounts for 1% of all cases of melanoma, being an aggressive subtype with poor prognosis, with 5-year overall survival of 10-20%. Mucosal melanoma of the oral cavity corresponds to 0.5% of all malignant tumors in the oral cavity and 25% of mucosal melanomas located in the head and neck. It has an anatomical distribution of predominance in the sinonasal tract 70%, oral cavity 20% and other locations such as larynx and pharynx. Some probable risk factors described are chronic mechanical trauma, ethylism, smoking, formaldehyde, however its etiology remains uncertain. We present the case of a 77-year-old female patient successfully treated by inferior maxillectomy and selective left cervical dissection. (provided by Infomedic International)

Roles of the α1B-Adrenergic Receptor Phosphorylation Domains in Signaling and Internalization.

The function of the α1B-adrenergic receptor phosphorylation sites previously detected by mass spectrometry was evaluated by employing mutants, substituting them with non-phosphorylatable amino acids. Substitution of the intracellular loop 3 (IL3) sites did not alter baseline or stimulated receptor phosphorylation, whereas substitution of phosphorylation sites in the carboxyl terminus (Ctail) or both domains (IL3/Ctail) markedly decreased receptor phosphorylation. Cells expressing the IL3 or Ctail receptor mutants exhibited a noradrenaline-induced calcium-maximal response similar to those expressing the wild-type receptor, and a shift to the left in the concentration-response curve to noradrenaline was also noticed. Cells expressing the IL3/Ctail mutant exhibited higher apparent potency and increased maximal response to noradrenaline than those expressing the wild-type receptor. Phorbol ester-induced desensitization of the calcium response to noradrenaline was reduced in cells expressing the IL3 mutant and abolished in cells in which the Ctail or the IL3/Ctail were modified. In contrast, desensitization in response to preincubation with noradrenaline was unaffected in cells expressing the distinct receptor mutants. Noradrenaline-induced ERK phosphorylation was surprisingly increased in cells expressing IL3-modified receptors but not in those expressing receptors with the Ctail or IL3/Ctail substitutions. Our data indicate that phosphorylation sites in the IL3 and Ctail domains mediate and regulate α1B-adrenergic receptor function. Phorbol ester-induced desensitization seems to be closely associated with receptor phosphorylation, whereas noradrenaline-induced desensitization likely involves other elements.

Historiographical approaches to biogeography: a critical review.

We performed a critical review of the historiographical studies on biogeography. We began with the pioneering works of Augustin and Alphonse de Candolle. Then, we analyzed the historical accounts of biogeography developed by (1) Martin Fichman and his history on the extensionism-permanentism debate; (2) Gareth Nelson and his critique of the Neo-Darwinian historiography of biogeography; (3) Ernst Mayr, with his dispersalist viewpoint; (4) Alan Richardson, who wrote a microhistory on the biogeographic model constructed by Darwin; (5) Michael Paul Kinch and the ideas discussed in the 19th century about the geographical distribution of living beings; (6) Janet Browne, who highlighted the importance of the pre-Darwinian naturalists; (7) Peter Bowler, who focused mainly on the influence of paleontology on biogeography; (8) James Larson, who looked into the practices of the naturalists of Northern Europe in the late 18th century; and (9) Malte Ebach, who like Larson, was more interested in analysing the practices rather than the ideas of naturalists who studied the geographical distribution of organisms. Finally, these works are compared with each other. There has not been a dominant paradigm in the construction of historical narratives of biogeography; however, they provide a useful context for understanding problems of biogeography that continue to be debated to this day.

Re-estimation of juvenile Isurus oxyrinchus growth in the Mexican Pacific through a multimodel inference approach and verification of growth band periodicity.

An update of the age and growth for juveniles of the short fin mako shark (I. oxyrinchus) from the Mexican Pacific is presented, based on the analysis of growth band counts from dorsal vertebrae of 198 individuals [110 females, 74-231 cm of total length (TL) and 88 males, 72-231 cm TL) caught during 2008-2018. New available information on vertebral growth band periodicity (biannual deposition in juveniles) and the convenience of using vertebrae form the dorsal region over the cervical region to count growth bands, as well as a multimodel approach, were used. The von Bertalanffy (VB) growth model, Gompertz, logistic and two parameters of VB (2-VB) were fitted to the length-at-age. Only ages ≤6 years were used for the fitting of the models and their performance was compared with the small-sample bias-corrected form of the Akaike information criterion (AICc), their differences ( ∆ i ) and weights ( w i ). Following a multimodel inference approach, the model averaged asymptotic length ( L ¯ inf ), length-at-age 0 ( L ¯ 0 ) and their unconditional standard error ( SE ¯ ), were estimated for each sex scenario using the three-parameter version of each model. The precision of growth band counts was acceptable for the different methods used and by two different readers. The centrum edge analysis (CEA) and marginal increment analysis (MIA) did not support the hypothesis of biannual band pair formation for juveniles, likewise for adults the periodicity could not be verified due to the small sample of large animals. Age was estimated assuming the formation of two pairs of growth bands per year during the first 5 years and one pair of bands per year afterwards considering direct validation information. The estimated ages in years ranged from 0-14 for females and 0-6 for males. The Kimura likelihood ratio test showed no differences in the growth curves of juveniles by sex (P > 0.05). According to the AICc, the 2-VB model better fitted the length-at-age data for combined sexes (Linf = 386.4 cm, k = 0.12 years-1 , L0 = 70 cm). The model averaged L ¯ inf and L ¯ 0 were 378.3 cm ( SE ¯ = 64.5 ) and 69.5 cm ( SE ¯ = 6.3 ), respectively. The growth parameters determined for juveniles of I. oxyrinchus are similar to those estimated in other regions, showing relatively fast growth rate as previously reported, medium longevity in comparison to other shark species and natural mortality close to that reported in the last stock assessment for the North Pacific Ocean. These life-history parameters should be considered to evaluate the population in the region and to develop better fishery management and conservation measures.

Genomic-based microsatellite development for Ternstroemia (Pentaphylacaceae) and transferability to other Ericales.

BACKGROUND: The genus Ternstroemia is associated with the vulnerable tropical montane cloud forest in Mexico and with other relevant vegetation types worldwide. It contains threatened and pharmacologically important species and has taxonomic issues regarding its species limits. This study describes 38 microsatellite markers generated using a genomic-based approach. METHODS AND RESULTS: We tested 23 of these markers in a natural population of Ternstroemia lineata. These markers are highly polymorphic (all loci polymorphic with 3-14 alleles per locus and expected heterozygosity between 0.202 and 0.908), most of them (19 out of 23) are in Hardy-Weinberg Equilibrium and free of null alleles (18 out of 23). Also we found no evidence of linkage among them. Finally, we tested the transferability to six other American species of Ternstroemia, two other Pentaphylacaceae species, and four species from different families within the order Ericales. CONCLUSIONS: These molecular resources are promising tools to investigate genetic diversity loss and as barcodes for ethnopharmacological applications and species delimitation in the family Pentaphylacaceae and some Ericales, among other applications.

Taquicardia ventricular asociada a mutación en el gen de ankirina B / Ventricular tachycardia associated to a mutation in the ankyrin B gen

Resumen Se presenta el caso de una mujer de 14 años, con taquicardiomiopatía secundaria a taquicardia ventricular. Se evidenció la presencia de una variante de significado incierto en el gen ANK2, por lo que se consideró un posible síndrome de ankirina B. La paciente fue tratada con éxito a través de ablación con radiofrecuencia. Tras dicho procedimiento, tuvo recuperación completa de su función ventricular izquierda y resolución de los complejos ventriculares prematuros y los episodios de taquicardia ventricular.

Abstract We report a case of a 14-year-old with tachycardiomyopathy due to ventricular tachycardia. A variant of uncertain significance of the ANK2 gene was identified, which is suggestive of a possible ankyrin-B syndrome. The patient underwent a successful radiofrequency ablation. After the procedure, the patient completely recovered her left ventricular function and there was resolution of the premature ventricular complexes and ventricular tachycardia.

Effect of cell size and thresholds in NDM/NVDM methods on recognizing areas of endemism.

Identifying areas of endemism has represented a great challenge, from the search for their definition, the design of methodologies, and the management of essential information to identify areas where the distributions of at least two taxa overlap. Endemicity Analysis is a widely used method that offers good results; however, an evaluation of the results is necessary. We evaluated the previous establishment of the minimum endemicity index of the species as a criterion to identify areas of endemism, applicated to a set of taxa with endemic and preferential distribution to the Sierra Madre Oriental. The taxa included in our analyses were 178 species of plants, vertebrates, and invertebrates. First, we varied the parameter set minimum score species in the software and the size of the cell. Next, we established criteria to evaluate the results obtained: areas supported by unique sets of species, good fit to the area, and sympatric distribution of taxa (extensive or homopatrid). After choosing the minimum ei with the best performance, we modified the study method for the endemicity analysis (Endemicity Analysis with Progressive Species Elimination). Our results indicate that the variation of the ei influenced the number of areas obtained by the program, decreasing considerably after evaluating the first criterion. The best fit to the cells occurred when we set 0.8 as the minimum ei in both cell sizes. The visually-preview of the sympatrid relationships allowed to recognize areas that do not present congruent distributions, although they meet the two previous criteria evaluated. The areas of endemism identified at different scales and those identified with the implementation of our modification were complementary.

Lactato como marcador temprano de hipoxia cerebral en pacientes neurológicos bajo anestesia general: una revisión sistemática / Lactate as an early marker of cerebral hypoxia in neurological patients under general anesthesia: a systematic review

Resumen: Las complicaciones neurológicas perioperatorias secundarias a hipoxia durante procedimientos de sedación y anestesia general son frecuentes en cirugía cardiovascular y en pacientes con comorbilidades. Sin embargo, hasta el momento no existe un consenso para el diagnóstico de estas posibles complicaciones. En pacientes con trauma encefálico severo y/o hemorragia subaracnoidea el lactato cerebral no fue útil para predicción de hipoxia cerebral; pese a ello, la relación de lactato/piruvato podría ser una herramienta para diagnóstico intraoperatorio de hipoxia cerebral aguda. Los estudios sugieren que éste debe asociarse a otros marcadores y/o a monitoreo multimodal. Es necesario realizar estudios que evalúen su valor predictivo para hipoxia cerebral.

Abstract: Perioperative neurological complications secondary to hypoxia during sedation and general anesthesia procedures are frequent in cardiovascular surgery, and in patients with comorbidities. However, so far there is no consensus for the diagnosis of these possible complications. In patients with head trauma severe and/or subarachnoid hemorrhage cerebral lactate was not useful for predicting cerebral hypoxia, however the lactate/pyruvate ratio could be a tool for intraoperative diagnosis of acute cerebral hypoxia. Studies suggest that it must be associated with other markers or multimodal monitoring. Further studies are needed to evaluate lactate predictive value for the diagnosis of cerebral hypoxia.

G protein-coupled receptors as therapeutic target.

Receptors are proteins coded by DNA, some of which have already been crystalized, thus allowing the details of their structure at the atomic level and some aspects of their function to be known. This review focuses on the most diverse and abundant family of receptors, G protein-coupled receptors. This family of receptors recognizes and mediates the action of several endogenous ligands (hormones, neurotransmitters, growth factors and local hormones) and also intervenes in the pathogenesis of various diseases, which is why they are targeted by approximately 30 to 40% of medications that are used in daily clinical practice and of various illegal drugs as well. X-ray crystallography is one of the essential tools that has allowed to observe the structure of these receptors in the amino acids that participate in this interaction, which allows to know the binding site of the endogenous ligand and of synthetic molecules that act on them to modulate their action. Molecular modeling or "docking" is also a computational bioinformatics tool that supports research on receptor-ligand binding, which allows the design and development of increasingly specific drugs. These developments have brought along significant changes in fundamental pharmacodynamic concepts.

Los receptores son proteínas codificadas por el ADN, algunos de los cuales ya han sido cristalizados, lo que permite conocer los detalles de su estructura a nivel atómico y algunos aspectos de su función. Esta revisión se enfoca en los más diversos y abundantes, los receptores acoplados a la proteína G. Esta familia de receptores reconoce y media la acción de varios ligandos endógenos (hormonas, neurotransmisores, factores de crecimiento y hormonas locales) y también interviene en la patogenia de diversas enfermedades, por lo que son el blanco terapéutico de aproximadamente 30 a 40 % de los medicamentos que se emplean en la práctica clínica cotidiana y de diversas drogas ilegales. La cristalografía de rayos X es una de las herramientas clave que ha permitido observar la estructura de estos receptores en los aminoácidos que participan en esta interacción, lo que posibilita conocer el sitio de unión del ligando endógeno y de moléculas sintéticas que actúan sobre ellos para modular su acción. El modelado molecular es también una herramienta bioinformática computacional que apoya la investigación sobre la unión receptor-ligando, que hace posible el diseño y desarrollo de fármacos cada vez más específicos. A estos desarrollos se suman importantes cambios en los conceptos farmacodinámicos fundamentales.

Los receptores acoplados a proteínas G como blanco terapéutico / G protein-coupled receptors as therapeutic target

Resumen Los receptores son proteínas codificadas por el ADN, algunos de los cuales ya han sido cristalizados, lo que permite conocer los detalles de su estructura a nivel atómico y algunos aspectos de su función. Esta revisión se enfoca en los más diversos y abundantes, los receptores acoplados a la proteína G. Esta familia de receptores reconoce y media la acción de varios ligandos endógenos (hormonas, neurotransmisores, factores de crecimiento y hormonas locales) y también interviene en la patogenia de diversas enfermedades, por lo que son el blanco terapéutico de aproximadamente 30 a 40 % de los medicamentos que se emplean en la práctica clínica cotidiana y de diversas drogas ilegales. La cristalografía de rayos X es una de las herramientas clave que ha permitido observar la estructura de estos receptores en los aminoácidos que participan en esta interacción, lo que posibilita conocer el sitio de unión del ligando endógeno y de moléculas sintéticas que actúan sobre ellos para modular su acción. El modelado molecular es también una herramienta bioinformática computacional que apoya la investigación sobre la unión receptor-ligando, que hace posible el diseño y desarrollo de fármacos cada vez más específicos. A estos desarrollos se suman importantes cambios en los conceptos farmacodinámicos fundamentales.

Abstract Receptors are proteins coded by DNA, some of which have already been crystalized, thus allowing the details of their structure at the atomic level and some aspects of their function to be known. This review focuses on the most diverse and abundant family of receptors, G protein-coupled receptors. This family of receptors recognizes and mediates the action of several endogenous ligands (hormones, neurotransmitters, growth factors and local hormones) and also intervenes in the pathogenesis of various diseases, which is why they are targeted by approximately 30 to 40% of medications that are used in daily clinical practice and of various illegal drugs as well. X-ray crystallography is one of the essential tools that has allowed to observe the structure of these receptors in the amino acids that participate in this interaction, which allows to know the binding site of the endogenous ligand and of synthetic molecules that act on them to modulate their action. Molecular modeling or "docking" is also a computational bioinformatics tool that supports research on receptor-ligand binding, which allows the design and development of increasingly specific drugs. These developments have brought along significant changes in fundamental pharmacodynamic concepts.

Click synthesis of novel dendronized curcumin and analogs. Strengthening of physicochemical properties toward biological applications.

Curcumin and its analogs, chalcones, and C5-monocarbonyl are molecules of great therapeutic potential, but their poor stability and hydrophobicity have hampered their extensive use in clinical trials. Therefore, significant efforts have been made in materials science to improve their physicochemical properties. In this study, we propose dendronization as a synthetic strategy to strengthen some physicochemical properties such as solubility and stability of curcumin and analogs, taking advantage of the click chemistry (CuAAC) to attach second-generation polyester dendrons to the unsaturated cores. The dendronization, with the subsequent formation of aromatic triazole groups as linkers, not only modified the solubility and stability of the molecular systems but also favored the diketo tautomeric form of curcumin, as demonstrated spectroscopically. This result is significant since the diketo tautomer, which preserves the antioxidant properties of curcumin, is the most biologically active form. The hydrophobic/hydrophilic balance, achieved after dendronization, allowed the solubilization of the chromophoric molecules in buffered solutions at relevant pH values (7.4 and 6.4). Furthermore, the stability of all molecules was also upgraded since UV-vis absorption spectra did not exhibit modified profiles after 7 days at physiologic pH. From photochemical stability experiments irradiating at 415 nm, the dendritic derivatives containing triazole linkers were more susceptible to being degraded. All derivatives exhibited emission properties according to the length of each conjugate fragment. Fluorescence experiments evidenced the role of dendrons in preventing emission quenching by aggregation and exhibited differentiated emission behavior depending on the linker type (triazole or ester) between the chromophoric core and the polyester dendrons.

Gold nanoparticle-catalysed functionalization of carbon-hydrogen bonds by carbene transfer reactions.

Gold nanoparticles stabilized by NHC ligands and supported onto reduced graphene oxide (rGO) catalyse the functionalization of cyclohexane and benzene C-H bonds upon insertion of carbene CHCO2Et (from N2CHCO2Et) groups. This is the first example in which such Csp3-H or Csp2-H bonds are functionalized with this strategy with nanoparticulated gold. This Au-NP@rGO material shows an exceptional activity, providing TON values 5-10 times higher than those already reported for molecular gold catalysts. Recyclability is also effective, reaching an accumulated TON value of 1400 after six consecutive uses.

Reduced Graphene Oxides as Carbocatalysts in Acceptorless Dehydrogenation of N-Heterocycles.

The catalytic properties of graphene-derived materials are evaluated in acceptorless dehydrogenation of N-heterocycles. Among them, reduced graphene oxides (rGOs) are active (quantitative yields in 23 h) under mild conditions (130 °C) and act as efficient heterogeneous carbocatalysts. rGO exhibits reusability and stability at least during eight consecutive runs. Mechanistic investigations supported by experimental evidence (i.e., organic molecules as model compounds, purposely addition of metal impurities and selective functional group masking experiments) suggest a preferential contribution of ketone carbonyl groups as active sites for this transformation.

Historical biogeography of the genus Rhadinaea (Squamata: Dipsadinae).

Multiple geological and climatic events have created geographical or ecological barriers associated with speciation events, playing a role in biological diversification in North and Central America. Here, we evaluate the influence of the Neogene and Quaternary geological events, as well as the climatic changes in the diversification of the colubrid snake genus Rhadinaea using molecular dating and ancestral area reconstruction. A multilocus sequence dataset was generated for 37 individuals of Rhadinaea from most of the biogeographical provinces where the genus is distributed, representing 19 of the 21 currently recognized species, and two undescribed species. Our analyses show that the majority of the Rhadinaea species nest in two main clades, herein identified as "Eastern" and "Southern". These clades probably diverged from each other in the early Miocene, and their divergence was followed by 11 divergences during the middle to late Miocene, three divergences during the Pliocene, and six divergences in the Pleistocene. The ancestral distribution of Rhadinaea was reconstructed across the Sierra Madre del Sur. Our phylogenetic analyses do not support the monophyly of Rhadinaea. The Miocene and Pliocene geomorphology, perhaps in conjunction with climate change, appears to have triggered the diversification of the genus, while the climatic changes during the Miocene probably induced the diversification of Rhadinaea in the Sierra Madre del Sur. Our analysis suggests that the uplifting of the Trans-Mexican Volcanic Belt and Chiapan-Guatemalan highlands in this same period resulted in northward and southward colonization events. This was followed by more recent, independent colonization events in the Pliocene and Pleistocene involving the Balsas Basin, Chihuahuan Desert, Pacific Coast, Sierra Madre Occidental, Sierra Madre Oriental, Sierra Madre del Sur, Trans-Mexican Volcanic Belt, and Veracruz provinces, probably driven by the climatic fluctuations of the time.

Mercury (Hg) and selenium (Se) content in the shark Mustelus henlei (Triakidae) in the northern Mexican Pacific.

Mercury and selenium were assessed in Mustelus henlei, which is a carnivorous predatory shark that is important for the coastal communities of the northern Mexican Pacific (NMP). Sixty-two individuals were sampled; muscle and liver were isolated and analyzed by atomic absorption spectrophotometry. The mean Hg concentrations (wet weight) obtained for muscle (0.08 ± 0.10 µg g-1) and liver (0.09 ± 0.26 µg g-1) were below the allowed limits (< 1.0 µg g-1 Hg). The average Se concentration was 0.03 ± 0.01 µg g-1 in muscle and 0.13 ± 0.05 µg g-1 in liver. The Se/Hg molar ratio of muscle was 1.83; however, the selenium health benefit value (HBVSe) was of 0.08. We calculated that an adult man (70 kg), an adult woman (60 kg), and a child (16 kg) could consume 1595, 838, and 223 g/week of M. henlei muscle, respectively, without risks to health. In conclusion, the concentrations and molar ratio of Hg and Se in M. henlei muscle mean that consumption of this shark's meat does not represent neither a benefit nor a public health risk.

Glycogen Synthase Kinase-3 modulates α1A-adrenergic receptor action and regulation.

The possibility that glycogen synthase kinase 3 (GSK3) could modulate α1A-adrenergic receptor (α1A-AR) function and regulation was tested employing LNCaP and HEK293 cells transfected to express the enhanced green fluorescent protein-tagged human α1A-AR. Receptor phosphorylation and internalization, intracellular free calcium, α1A-AR-GSK3 colocalization, and coimmunoprecipitation were studied. The effects of the pharmacological GSK3 inhibitor, SB-216763, and the coexpression of a dominant-negative mutant of this kinase, as well as the signaling, desensitization, and internalization of receptors with S229, S258, S352, and S381 substitutions for alanine or aspartate, were also determined. SB-216763 inhibited agonist- and phorbol myristate acetate (PMA)-mediated α1A-AR phosphorylation, reduced oxymetazoline-induced desensitization, and magnified that induced by PMA. Agonists and PMA increased receptor-GSK3 colocalization and coimmunoprecipitation. Expression of a dominant-negative GSK3 mutant reduced agonist- but not PMA-induced receptor internalization. α1A-AR with the GSK3 putative target sites mutated to alanine exhibited reduced phosphorylation and internalization in response to agonists and increased PMA-induced desensitization. Agonist-induced, but not PMA-induced, receptor-ß arrestin intracellular colocalization was diminished in cells expressing the GSK3 putative target sites mutated to alanine. Our data indicated that GSK3 exerts a dual action on α1A-AR participating in agonist-mediated desensitization and internalization and avoiding PMA-induced desensitization.

Roles of the G protein-coupled receptor kinase 2 and Rab5 in α1B-adrenergic receptor function and internalization.

Cells expressing eGFP-tagged Rab5 (wild-type or the GDP-Rab5 mutant) and the DsRed-tagged α1B-adrenergic receptors were employed and the roles of GRK2 were studied utilizing paroxetine and the dominant-negative mutant of GRK2 (DN-GRK2). The following parameters were studied: a) FRET (as an index of α1B-adrenergic receptor-Rab5 interaction): b) intracellular accumulation of DsRed fluorescence (receptor internalization); c) α1B-adrenergic receptor phosphorylation, and d) noradrenaline-induced increase in intracellular calcium concentration. Noradrenaline increased α1B-adrenergic receptor-Rab5 interaction, which was blocked by paroxetine and by expression of the dominant-negative GRK2 mutant. Similarly, paroxetine and expression of the DN-GRK2 or the GDP-Rab5 mutants markedly decreased receptor internalization, α1B-adrenergic receptor phosphorylation, and attenuated the ability of the adrenergic agonist to induce homologous desensitization (calcium signaling). The S406, 410,412A α1B-adrenergic receptor mutant did not reproduce the actions of GRK2 inhibition. The data indicate that GRK2 and Rab5 play key roles in α1B-adrenergic receptor phosphorylation, internalization, and desensitization. The possibility that Rab5 might form part of a signaling complex is suggested, as well as that GDP-Rab5 might interfere with the ability of GRK2 to catalyze α1B-adrenergic receptor phosphorylation.

Sites phosphorylated in human α1B-adrenoceptors in response to noradrenaline and phorbol myristate acetate.

Phosphorylation of the human α1B-adrenergic receptor (fused with the green fluorescent protein) was studied employing the inducible Flp-ln HEK293 T-Rex system for expression. Serine/alanine substitutions were performed in five sites corresponding to those previously identified as phosphorylation targets in the hamster ortholog. Desensitization was decreased in these mutants but receptor phosphorylation was still clearly detected. The protein phosphorylation of the wild-type receptor (fused to the green fluorescent protein) was studied, using mass spectrometry, under baseline and stimulated conditions (noradrenaline or phorbol myristate acetate). Basal phosphorylation was detected at sites located at the intracellular loop 3 and carboxyl terminus, and the number of sites detected increased under agonist activation and stimulation of protein kinase C. The phosphorylation patterns differed under the distinct conditions. Three of the phosphorylation sites detected in this work corresponded to those observed in the hamster receptor. The phosphorylation sites detected included the following: a) at the intracellular loop 3: serines 246, 248, 257, 267, and 277; and threonines 252, 264, and 268, and b) at the carboxyl terminus: serines 396, 400, 402, 406, 423, 425, 427, 455, and 470, and threonines 387, 392, 420, and 475. Our data indicate that complex phosphorylation patterns exist and suggest the possibility that such differences could be relevant in receptor function and subcellular localization.

Improving Catalyst Activity in Hydrocarbon Functionalization by Remote Pyrene-Graphene Stacking.

A copper complex bearing an N-heterocyclic carbene ligand with a pyrene "tail" attached to the backbone has been prepared and supported on reduced graphene oxide (rGO). The free and supported copper materials have been employed as homogeneous and heterogeneous catalysts in the functionalization of hydrocarbons such as n-hexane, cyclohexane, and benzene through incorporation of the CHCO2 Et unit from ethyl diazoacetate. The graphene-anchored complex displays higher reaction rates and induces higher yields than its soluble counterpart, features that can be rationalized in terms of a decrease in electron density at the metal center due to a remote net electronic flux from the supported copper complex to the graphene surface.