Exploiting the 1,2,3-triazolium motif in anion-templated formation of a bromide-selective rotaxane host assembly

Stimulated by the efficacy of copper (I) catalysed Huisgen-type 1,3-dipolar cycloaddition of terminal alkynes and organic azides to generate 1,4-disubstituted 1,2,3-triazole derivatives, the importance of ‘click’ chemistry in the synthesis of organic and biological molecular systems is ever increasing.[1] The mild reaction conditions have also led to this reaction gaining favour in the construction of interlocked molecular architectures.[2-4] In the majority of cases however, the triazole group simply serves as a covalent linkage with no function in the resulting organic molecular framework. More recently a renewed interest has been shown in the transition metal coordination chemistry of triazole ligands.[3, 5, 6] In addition novel aryl macrocyclic and acyclic triazole based oligomers have been shown to recognise halide anions via cooperative triazole C5-H….anion hydrogen bonds.[7] In light of this it is surprising the potential anion binding affinity of the positively charged triazolium motif has not, with one notable exception,[8] been investigated. With the objective of manipulating the unique topological cavities of mechanically bonded molecules for anion recognition purposes, we have developed general methods of using anions to template the formation of interpenetrated and interlocked structures.[9-13] Herein we report the first examples of exploiting the 1,2,3-triazolium group in the anion templated formation of pseudorotaxane and rotaxane assemblies. In an unprecedented discovery the bromide anion is shown to be a superior templating reagent to chloride in the synthesis of a novel triazolium axle containing [2]rotaxane. Furthermore the resulting rotaxane interlocked host system exhibits the rare selectivity preference for bromide over chloride...

A three-nucleotide mutation altering the Maize streak virus Rep pRBR-interaction motif reduces symptom severity in maize and partially reverts at high frequency without restoring pRBR-Rep binding

Geminivirus infectivity is thought to depend on interactions between the virus replication-associated proteins Rep or RepA and host retinoblastoma-related proteins (pRBR), which control cell-cycle progression. It was determined that the substitution of two amino acids in the Maize streak virus (MSV) RepA pRBR-interaction motif (LLCNE to LLCLK) abolished detectable RepA-pRBR interaction in yeast without abolishing infectivity in maize. Although the mutant virus was infectious in maize, it induced less severe symptoms than the wild-type virus. Sequence analysis of progeny viral DNA isolated from infected maize enabled detection of a high-frequency single-nucleotide reversion of C(601)A in the 3 nt mutated sequence of the Rep gene. Although it did not restore RepA-pRBR interaction in yeast, sequence-specific PCR showed that, in five out of eight plants, the C(601)A reversion appeared by day 10 post-inoculation. In all plants, the C(601)A revertant eventually completely replaced the original mutant population, indicating a high selection pressure for the single-nucleotide reversion. Apart from potentially revealing an alternative or possibly additional function for the stretch of DNA that encodes the apparently non-essential pRBR-interaction motif of MSV Rep, the consistent emergence and eventual dominance of the C(601)A revertant population might provide a useful tool for investigating aspects of MSV biology, such as replication, mutation and evolution rates, and complex population phenomena, such as competition between quasispecies and population turnover. © 2005 SGM.

RAD51-associated Protein 1 (RAD51AP1) Interacts with the Meiotic Recombinase DMC1 through a Conserved Motif

Homologous recombination (HR) reactions mediated by the RAD51 recombinase are essential for DNA and replication fork repair, genome stability, and tumor suppression. RAD51-associated protein 1 (RAD51AP1) is an important HR factor that associates with and stimulates the recombinase activity of RAD51. We have recently shown that RAD51AP1 also partners with the meiotic recombinase DMC1, displaying isoform-specific interactions with DMC1. Here, we have characterized the DMC1 interaction site in RAD51AP1 by a series of truncations and point mutations to uncover a highly conserved WVPP motif critical for DMC1 interaction but dispensable for RAD51 association. This RAD51AP1 motif is reminiscent of the FVPP motif in the tumor suppressor protein BRCA2 that mediates DMC1 interaction. These results further implicate RAD51AP1 in meiotic HR via RAD51 and DMC1.

Víctimas de un experimento: Conflicto multicultural en el programa de oportunidades

This article presents a reflection of the application of multiculturality principles into tertiary educational programs at the University of Los Andes, Bogota Colombia. The main focus of this paper is debating the concept of 'positive discrimination' as a challenge taken by educational centres in societies with cultural diversity populations.

Programa Piloto de Diseño Promoción y Desarrollo de Productos con Alto Valor Agregado en la Empresa Peruana

Este proyecto se desarrollo por iniciativa de las autoras y con el apoyo de un grupo interdisciplinario, con el interés común de desarrollar una investigación académica cuyo resultado sea de utilidad para el desarrollo del sector productivo artesanal Peruano. El proceso de investigación nace a partir de una observación de campo acerca de la problemática del producto artesanal Peruana y enfocada en los aspectos comerciales, de diseño y producción. Esta observación se centro en Cajamarca (por ser el departamento menos intervenido por otras investigaciones en este tema) en la zona de Aylambo y Cruz Blanca, en los talleres artesanales que desarrollan productos cerámicos. A partir de un análisis de tipo FODA de los productos y de su contexto de desarrollo, encontramos que los artesanos que trabajan con los empresarios exportadores, requieren un tipo de capacitación que les permita desarrollar su trabajo mediante un proceso orientado a cumplir con exigencias técnicas y de diseño para el desarrollo de productos validos como oferta exportable. Como punto de partida se recurrió a las instituciones no gubernamentales y del gobierno, que promueven el sector artesanal Peruano (Prompex, Adex, Proyecto PARA, IMPART) para conocer su opinión respecto a los mercados objetivos de este sector, y para adoptar como parte del proyecto, lo vigente respecto a las políticas y planes de comercialización. Para entender la contraparte comercial de este sector artesanal recurrimos a empresas privadas exportadoras con muchos años de experiencia, para ello contamos con la colaboración de empresas como Allpa, Manos Amigas, Novica. A partir de la observación de campo preliminar y de la información recogida de los expertos consultados, se realizo un diagnostico de la situación productiva en este sector. En base a la definición del problema, se establecieron las estrategias y metodologías para el diseño de la investigación, siendo parte de estas estrategias, la realización de un taller de desarrollo de productos en Cajamarca. Las estrategias tuvieron como enfoque principal la definición de metodologías de trabajo, cuya aplicación sea posible en el marco del contexto económico, político y cultural en el que se desarrolla este sector en la realidad inmediata del país. El proyecto culmina con la presentación de una propuesta que mas allá de abarcar únicamente lo metodológico en el área del diseño, presenta también ‘modelos’ de trabajo entre los diferentes actores que intervienen en el sector, de manera que a través de estrategias colaborativas se pueda potenciar el crecimiento del sector y beneficiar el desarrollo del artesano.

Pt(II) bipyridyl complexes bearing substituted fluorenyl motif on the bipyridyl and acetylide ligands : synthesis, photophysics, and reverse saturable absorption

A series of Pt(II) diimine complexes bearing benzothiazolylfluorenyl (BTZ-F8), diphenylaminofluorenyl (NPh2- F8), or naphthalimidylfluorenyl (NI-F8) motifs on the bipyridyl or acetylide ligands (Pt-4−Pt-8), (i.e., {4,4′-bis[7-R1-F8-(≡)n-]bpy}Pt(7- R2-F8- ≡ -)2, where F8 = 9,9′-di(2-ethylhexyl)fluorene, bpy = 2,2′- bipyridine, Pt-4: R1 = R2 = BTZ, n = 0; Pt-5: R1 = BTZ, R2 = NI, n = 0; Pt-6: R1 = R2 = BTZ, n = 1; Pt-7: R1 = BTZ, R2 = NPh2, n = 1; Pt- 8: R1 = NPh2, R2 = BTZ, n = 1) were synthesized. Their ground-state and excited-state properties and reverse saturable absorption performances were systematically investigated. The influence of these motifs on the photophysics of the complexes was investigated by spectroscopic methods and simulated by time-dependent density functional theory (TDDFT). The intense absorption bands below 410 nm for these complexes is assigned to predominantly 1π,π* transitions localized on either the bipyridine or the acetylide ligands; while the broad low-energy absorption bands between 420 and 575 nm are attributed to essentially 1MLCT (metal-to-ligand charge transfer)/ 1LLCT (ligand-to-ligand charge transfer) transitions, likely mixed with some 1ILCT (intraligand charge transfer) transition for Pt-4−Pt-7, and predominantly 1ILCT transition admixing with minor 1MLCT/1LLCT characters for Pt-8. The different substituents on the acetylide and bipyridyl ligands, and the degrees of π-conjugation in the bipyridyl ligand influence both the 1π,π* and charge transfer transitions pronouncedly. All complexes are emissive at room temperature. Upon excitation at their respective absorption band maxima, Pt-4, Pt-6, and Pt-8 exhibit acetylide ligand localized 1π,π* fluorescence and 3MLCT/3LLCT phosphorescence in CH2Cl2, while Pt-5 manifests 1ILCT fluorescence and 3ILCT phosphorescence. However, only 1LLCT fluorescence was observed for Pt-7 at room temperature. The nanosecond transient absorption study was carried out for Pt-4−Pt-8 in CH3CN. Except for Pt-7 that contains NPh2 at the acetylide ligands, Pt-4−Pt-6 and Pt-8 all exhibit weak to moderate excited-state absorption in the visible spectral region. Reverse saturable absorption (RSA) of these complexes was demonstrated at 532 nm using 4.1 ns laser pulses in a 2 mm cuvette. The strength of RSA follows this trend: Pt-4 > Pt-5 > Pt-7 > Pt-6 > Pt-8. Incorporation of electron-donating substituent NPh2 on the bipyridyl ligand significantly decreases the RSA, while shorter π-conjugation in the bipyridyl ligand increases the RSA. Therefore, the substituent at either the acetylide ligands or the bipyridyl ligand could affect the singlet and triplet excited-state characteristics significantly, which strongly influences the RSA efficiency.

Etapas del cambio en personas inactivas tras un programa de promoción de la actividad física en Atención Primaria

Objetivo El objetivo del estudio fue evaluar las Etapas del cambio en relación con la actividad física y el estado de salud general entre personas que participaron en un Programa de promoción de la actividad física (PPAF) de 12 semanas frente a un grupo control. Diseño Ensayo clínico aleatorizado. Participantes Noventa y ocho personas inactivas de ambos sexos con una edad media de 62,82 años procedentes de 2 centros de Atención Primaria del Distrito Sanitario Costa del Sol. Intervención Un PPAF organizado en grupos y siguiendo los criterios del Colegio Americano de Medicina del Deporte, 2 sesiones semanales de 60 min durante 12 semanas. Mediciones principales La variable principal de resultado fue resistencia al cambio en relación con la actividad física. La variable secundaria fue el estado de salud general (componentes físicos y mentales), determinado con el cuestionario de salud general SF12. Resultados Se encontraron diferencias significativas en las etapas del cambio a favor del grupo experimental (p < 0,05). No se encontraron diferencias estadísticamente significativas entre grupos después de la intervención en el estado general de salud. Conclusión Las etapas del cambio se modificaron en las personas inactivas que realizaron el PPAF en Atención Primaria. Futuros estudios son necesarios para identificar qué factores del entorno de los participantes influyen en la resistencia al cambio de la actividad física. Abstract Objective This study has aimed to evaluate the stages of change in relation to physical activity and overall health status among persons who participated in a 12-week Physical activity promotion program (PAPP) compared to a control group. Design Randomized clinical trial. Participants The study included 98 inactive persons of both sexes with a mean age of 62.82 years from 2 of Primary Care Centers of the Malaga Health Care District. Interventions A PAPP organized in groups according to the American College of Sports Medicine criteria including two weekly sessions of 60 minutes each for 3 months. Main measures The primary outcome was to assess resistance to change in relation to physical activity. The secondary variable was overall health (physical and mental components) determined with the SF12 general health questionnaire. Results Significant differences were found in the stages of change (P<.05). There were no significant differences found in general health status improvement in regards to the initial assessment. Conclusion The stages of change were modified in the inactive persons who carried out the PAPP in Primary Care. Future studies are needed to identify which environmental factors influence the resistance to change in physical activity of the participants.

Cambios hematológicos tras un programa de promoción de actividad física en sujetos inactivos. Ensayo aleatorizado controlado

Objetivo Comparar los cambios antropométricos y bioquímicos en personas inactivas, que realizan un programa de actividad física frente a los que no lo realizan desde los Centros de Atención Primaria. Métodos Cien personas inactivas de ambos sexos, mayores de 55 años fueron aleatorizadas a un grupo experimental (n = 50) y a un grupo control (n = 50). Se realizó un programa de promoción de actividad física siguiendo los criterios del Colegio Americano de Medicina del Deporte, de 60 min cada sesión, 2 sesiones por semana, durante 3 meses. Las medidas antropométricas incluyeron el índice de masa corporal y el porcentaje graso, y como variables bioquímicas el perfil lipídico, hematíes y la creatina kinasa. Resultados Completaron el estudio 75 personas. Esta investigación no presentó cambios significativos a nivel antropométrico, ni en las variables bioquímicas del perfil lipídico. Sí se observaron efectos clínicamente relevantes en la concentración de los hematíes de las mujeres que realizaron dicho programa. Conclusiones El efecto clínico global fue pequeño en las personas que realizaron el programa, pero relevante para la salud de la población. Esta intervención produce efectos a corto plazo en la bioquímica de las personas inactivas. Abstract in English Objective Compare anthropometry and biochemical changes in inactive people who participate in a physical activity program versus those who do not from the Primary Health Care Centers. Methods One hundred inactive subjects of both genders, 55 years and older, from Torremolinos, Spain were randomized into an experimental group (n = 50) and a control group (n = 50). A program promoting physical activity was carried out following the American Medical Society for Sport's Medicine criteria. The program included sessions a week for 3 months. Antropometric measurements included body mass index and fat percentage, and such as biochemical measures: the lipid profile, erythrocytes, and creatine kinase. Results Seventy-five persons completed the study. This research did not show significant changes to anthropometric or biochemical outcomes of the lipid profile. However, there were clinically relevant effects regarding red blood cells concentration in the women who participated in this program. Conclusions Overall clinical effect was small in those participating in the program, but relevant for the health of the population. This program has short-term effects on biochemistry results of inactive subjects.