The triplet excited state of the biocative compound thiabendazole. Characterization and suitability as reporter for cyclodextrin complexation

Fluorescence spectroscopy, laser flash photolysis (LPF), and density functional theory calculations have been performed to characterize the photobehavior of thiabendazole (1). Direct LFP of 1 results in the generation of a transient absorbing at λmax = 570 nm identified as the triplet excited state (31∗). The intersystem crossing quantum yield is 0.91, and the triplet energy is 288 kJ mol−1. The singlet–triplet energy gap is 84 kJ mol−1. The behavior of thiabendazole within CDs results in a marked enhancement of the triplet lifetime, this change is attributed to the mobility restrictions of included 1 imposed by the cyclodextrin cavities.Financial support from the MICINN (Grants: CTQ2009-11027/BQU, CTQ2010-19909 and pre-doctoral fellowship to P.B.) and the Generalitat Valenciana (Prometeo Program) is gratefully acknowledged.Bartovsky, P.; Domingo, LR.; Jornet Olivé, MD.; Miranda Alonso, MÁ.; Tormos Faus, RE. (2012). The triplet excited state of the biocative compound thiabendazole. Characterization and suitability as reporter for cyclodextrin complexation. Chemical Physics Letters. 525-526:166-170. https://doi.org/10.1016/j.cplett.2012.01.001S166170525-52

Mycobacterial dihydrofolate reductase inhibitors identified using chemogenomic methods and in vitro validation.

The lack of success in target-based screening approaches to the discovery of antibacterial agents has led to reemergence of phenotypic screening as a successful approach of identifying bioactive, antibacterial compounds. A challenge though with this route is then to identify the molecular target(s) and mechanism of action of the hits. This target identification, or deorphanization step, is often essential in further optimization and validation studies. Direct experimental identification of the molecular target of a screening hit is often complex, precisely because the properties and specificity of the hit are not yet optimized against that target, and so many false positives are often obtained. An alternative is to use computational, predictive, approaches to hypothesize a mechanism of action, which can then be validated in a more directed and efficient manner. Specifically here we present experimental validation of an in silico prediction from a large-scale screen performed against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. The two potent anti-tubercular compounds studied in this case, belonging to the tetrahydro-1,3,5-triazin-2-amine (THT) family, were predicted and confirmed to be an inhibitor of dihydrofolate reductase (DHFR), a known essential Mtb gene, and already clinically validated as a drug target. Given the large number of similar screening data sets shared amongst the community, this in vitro validation of these target predictions gives weight to computational approaches to establish the mechanism of action (MoA) of novel screening hit

Mojanda volcanic complex (Ecuador) : development of two adjacent contemporaneous volcanoes with contrasting eruptive styles magmatic suites

En el Norte del Ecuador, el Complejo Volcanico Mojanda esta formado por dos centros eruptivos contemporaneos, el Mojanda sensu stricto y el Fuya Fuya. No obstante su cercania, estos centros mostraron una historia y estilo eruptivo diferentes. En el Mojanda, lavas andeciticas y daciticas componen la mayor parte del volcan de base (Moj I). Despue‚s de la formaco¢n de una caldera, se construyo un nuevo cono (Moj II), comprendido de lavas, de flujos de escoria y una serie de brechas en la cumbre cuyas composiciones son de andesitas basalticas. Este cono fue parcialmente destruido luego por la formacion de una pequena caldera. El Fuya Fuya se construyo sobre el flanco oeste del Moj I, y fue contemporaneo con el Mojanda II. Su actividad empezo con viscosas extrusiones y domos de quimica andesitica y dacitica (FF I), seguidos por una intensa actividad piroclastica (FF II) durante la cual fueron emitidas dos caidas plinianas de pomez riolitica (R1 y R2) de gran volumen. Despue‚s, la actividad se volio mass efusiva con la construcio¢n de un edificio andesitico intermediario, el cono San Bartolo (FF III). La historia del San Bartolo termino con el colapso de la parte superior y del flanco oeste de este cono, el cual incluyo tambie‚n una parte del Mojanda II. El colapso genero una avalancha (FF IV) que fue acompanada por voluminosos flujos piroclasticos y fue seguida por la construccion de un complejo de domos (FF V) en la caldera de avalancha. Las series magmaticas de los dos centros muestran tendencias adakiticas las cuales estan mas marcadas en el Fuya Fuya que en el Mojanda, lo que sugiere origenes distintos. Sin embargo, existen argumentos para concluir que los dos volcanes comparten relacion a veces en su desarrollo y evolucion magmatica. Por ejemplo, el deposito pliniano R1 del FF II contiene clastos juveniles andesiticos derivados del Mojanda, una caracteristica que se repite en los flujos piroclasticos emitidos despue‚s del evento de avalancha en el Fuya Fuya. (Résumé d'Auteur

Vertical Distribution of Fish Larvae and Its Relation to Water Column Structure in the Southwestern Gulf of California.

v. ill. 23 cm.QuarterlyThe seasonal evolution of vertical distribution of fish larvae and its relationship with seasonal stratification, as measured by a quantitative stability parameter, were analyzed for a region off Bahı´a de La Paz in the southwestern Gulf of California. Samples were obtained with an opening closing net (505 mm) in 50-m depth strata from surface to 200-m depth in May, July, and October 2001 and February 2002. Significant differences in total larval abundance and in dominant species (mesopelagic and epipelagic) were found among strata from May to October. More larvae were found in maximum-stability strata (from 16G5 to 48G17 m depth) than below the pycnocline (from 100- to 150-m depth). In February, the 100-m-deep surface mixed layer had a weak pycnocline at its base, and no significant difference was found. Results show that vertical distribution of fish larvae in this area depends mainly on the seasonal evolution of the water column structure, with most fish larvae in the pycnocline, at the most stable stratum of the water column