Degradation of pheromone and plant volatile components by a same Odorant-Degrading Enzyme in the cotton leafworm, Spodoptera littoralis

Background: Odorant-Degrading Enzymes (ODEs) are supposed to be involved in the signal inactivation step within the olfactory sensilla of insects by quickly removing odorant molecules from the vicinity of the olfactory receptors. Only three ODEs have been both identified at the molecular level and functionally characterized: two were specialized in the degradation of pheromone compounds and the last one was shown to degrade a plant odorant. Methodology: Previous work has shown that the antennae of the cotton leafworm Spodoptera littoralis , a worldwide pest of agricultural crops, express numerous candidate ODEs. We focused on an esterase overexpressed in males antennae, namely SlCXE7. We studied its expression patterns and tested its catalytic properties towards three odorants, i.e. the two female sex pheromone components and a green leaf volatile emitted by host plants. Conclusion: SlCXE7 expression was concomitant during development with male responsiveness to odorants and during adult scotophase with the period of male most active sexual behaviour. Furthermore, SlCXE7 transcription could be induced by male exposure to the main pheromone component, suggesting a role of Pheromone-Degrading Enzyme. Interestingly, recombinant SlCXE7 was able to efficiently hydrolyze the pheromone compounds but also the plant volatile, with a higher affinity for the pheromone than for the plant compound. In male antennae, SlCXE7 expression was associated with both long and short sensilla, tuned to sex pheromones or plant odours, respectively. Our results thus suggested that a same ODE could have a dual function depending of it sensillar localisation. Within the pheromone-sensitive sensilla, SlCXE7 may play a role in pheromone signal termination and in reduction of odorant background noise, whereas it could be involved in plant odorant inactivation within the short sensilla.

Synthesis of the two isomers of the potential sex pheromone of Thaumetopoea pityocampa (Lepidoptera, Notodontidae) and related model compounds

The synthesis of the major component of the sex pheromone secretion of the processionary moth, Tkawnztopoeja pltyocampa (Denis and Schiff.) (Lepidoptera, Notodontidae), (Z)-13-hexadecen-ll-ynyl acetate (1), the corresponding (E)-isomer (2) and the four structurally related model compounds (Z⁄E,Z,Z)-5,9,13-hexadecatrienyl acetate (3), (Z⁄E,Z,Z)-3,7,ll-hexadecatrienyl acetate (4), (Z⁄E,E,Z)-7,9,13-hexadecatrienyl acetate (5) and (Z)-7-hexadecen-5-ynyl acetate (6) is described.

Short communication. Mutual pheromone antagonism in two sympatric corn borers, Sesamia nonagrioides and Ostrinia nubilalis, under field conditions

In previous studies, we demonstrated cross-antagonism in pheromone perception between pheromone componentsof the two corn (Zea mays L.) borers Sesamia nonagrioides Lefèbvre (Lepidoptera: Noctuidae) and Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) in the laboratory and in the field. The two pheromone components identified as responsible for this cross-antagonism were Z 11-16:Ald, a minor component of S. nonagrioides pheromone, and Z 11-14:Ac, the main component of the pheromone of the Z-strain of O. nubilalis, which inhibited the response of O. nubilalis and S. nonagrioides, respectively. Here, we study this antagonism phenomenon in the field by air permeation of maize plots with each of the two components separately and measurement of mating in caged couples of the two corn borers on treated and untreated plots during three years. A significant reduction in mating rates was observed on the permeated plots: 7% for S. nonagrioides and 12% for O. nubilalis. When dispenser charges (200 ng) were increased by 50% and 75% in the third year, no decrease in mating rates was recorded at either of the increased concentrations. On the other hand, the use of large cages resulted in an increase of 8% to 12% in the percentage of unmated females in each of the two corn borers suggesting that at more realistic field corn borer densities, 0,1 couples/plant instead of the 2 couples/plant used in this experiment, cross-antagonism in the two corn borers could be higher than that recorded in small cages.

A carboxylesterase, Esterase-6, modulates sensory physiological and behavioural response dynamics to pheromone in Drosophila

Background: Insects respond to the spatial and temporal dynamics of a pheromone plume, which implies not only a strong response to"odor on", but also to"odor off". This requires mechanisms geared toward a fast signal termination. Several mechanisms may contribute to signal termination, among which odorant-degrading enzymes. These enzymes putatively play a role in signal dynamics by a rapid inactivation of odorants in the vicinity of the sensory receptors, although direct in vivo experimental evidences are lacking. Here we verified the role of an extracellular carboxylesterase, esterase-6 (Est-6), in the sensory physiological and behavioral dynamics of Drosophila melanogaster response to its pheromone, cis-vaccenyl acetate (cVA). Est-6 was previously linked to post-mating effects in the reproductive system of females. As Est-6 is also known to hydrolyze cVA in vitro and is expressed in the main olfactory organ, the antenna, we tested here its role in olfaction as a putative odorant-degrading enzyme. Results: We first confirm that Est-6 is highly expressed in olfactory sensilla, including cVA-sensitive sensilla, and we show that expression is likely associated with non-neuronal cells. Our electrophysiological approaches show that the dynamics of olfactory receptor neuron (ORN) responses is strongly influenced by Est-6, as in Est-6° null mutants (lacking the Est-6 gene) cVA-sensitive ORN showed increased firing rate and prolonged activity in response to cVA. Est-6° mutant males had a lower threshold of behavioral response to cVA, as revealed by the analysis of two cVAinduced behaviors. In particular, mutant males exhibited a strong decrease of male-male courtship, in association with a delay in courtship initiation. Conclusions: Our study presents evidence that Est-6 plays a role in the physiological and behavioral dynamics of sex pheromone response in Drosophila males and supports a role of Est-6 as an odorant-degrading enzyme (ODE) in male antennae. Our results also expand the role of Est-6 in Drosophila biology, from reproduction to olfaction, and highlight the role of ODEs in insect olfaction. Keywords: carboxylesterase, esterase 6, olfaction, pheromone, signal termination

Educación ambiental como factor de cambio: conocer, interpretar y aprender para mejorar desde lo glocal

Primero comenzamos por describir la situación global histórica de la transformación del entorno. Luego se describe cómo evoluciona la Educación Ambiental bajo el concepto del desarrollo, constituyéndose como la Educación Ambiental para el Desarrollo Sustentable. Continuamos describiendo la situación de la EA a nivel internacional; se pasa luego al ámbito nacional, teniendo como escenario a México, aquí se hace un análisis del estado que guarda la EA en el país. Después se continua con el ámbito estatal, para lo cual se analiza la situación de la EA en el estado de Zacatecas, en este plano se toca el tema de la participación de las instituciones de educación superior en el intercambio de experiencias y conocimientos para el fortalecimiento de programas de EADS. Luego pasamos a un ámbito municipal, el caso a tratar es el municipio de Monte Escobedo Zacatecas, se hace una descripción general del municipio y se tratan los antecedentes que han motivado este proyecto, para luego pasar a describir el caso específico de la Sierra de Monte Escobedo; a partir de las características de ésta y retomando una propuesta previa de integrar la Sierra al sistema de Áreas Naturales Protegidas de México, se hacen dos propuestas: La primera es sobre el diseño de un Centro de Interpretación y Educación Ambiental; la segunda es para la realización de un Sendero de interpretación. Ambas propuestas pretenden contribuir al aprovechamiento sustentable de los recursos y desarrollo de la comunidad.

Comparative genomics of the odorant-binding and chemosensory protein gene families across the arthropoda: origin and evolutionary history of the chemosensory system

Chemoreception is a biological process essential for the survival of animals, as it allows the recognition of important volatile cues for the detection of food, egg-laying substrates, mates or predators, among other purposes. Furthermore, its role in pheromone detection may contribute to evolutionary processes such as reproductive isolation and speciation. This key role in several vital biological processes makes chemoreception a particularly interesting system for studying the role of natural selection in molecular adaptation. Two major gene families are involved in the perireceptor events of the chemosensory system: the odorant-binding protein (OBP) and chemosensory protein (CSP) families. Here, we have conducted an exhaustive comparative genomic analysis of these gene families in twenty Arthropoda species. We show that the evolution of the OBP and CSP gene families is highly dynamic, with a high number of gains and losses of genes, pseudogenes and independent origins of subfamilies. Taken together, our data clearly support the birth-and-death model for the evolution of these gene families with an overall high gene-turnover rate. Moreover, we show that the genome organization of the two families is significantly more clustered than expected by chance and, more important, that this pattern appears to be actively maintained across the Drosophila phylogeny. Finally, we suggest the homologous nature of the OBP and CSP gene families, dating back their MRCA (most recent common ancestor) to 380¿420 Mya, and we propose a scenario for the origin and diversification of these families.

Courtship and mating behaviour of the Mediterranean corn borer, Sesamia nonagrioides (Lepidoptera: Noctuidae)

Se describe la secuencia de cortejo y apareamiento de machos y hembras de Sesamia nonagrioides (Lefèbvre) en el laboratorio. Esta secuencia no varió en presencia o ausencia de plantas de maíz. Se estudió la capacidad de atracción de un sexo sobre el otro atando el individuo de un sexo y dejando libre al complementario. La secuencia de cortejo y apareo de las hembras atadas fue la misma que la de las no atadas, pero los machos atados permanecieron absolutamente inactivos. La edad de los adultos (1 día versus 2 días) no afectó al porcentaje de apareamiento. Se encontraron diferencias en la hora del inicio de la llamada de las hembras y en la edad de las hembras en la primera llamada entre la población estudiada y lo descrito para una población griega, diferencias que podrían estar relacionadas con el origen geográfico. Se discute el papel de los penachos abdominales de los machos en el vuelo de cortejo, rechazándose que estimulen el comportamiento de llamada de las hembras o que las atraigan. Cuando no se aplicaron feromonas, el porcentaje de apareamiento en el laboratorio o en el campo no varió cuando aumentó la densidad de la población. Sin embargo, en los campos en que se aplicó confusión sexual, el porcentaje de apareamiento aumentó al aumentar la densidad de adultos. En la discusión se aportan algunas consecuencias para la investigación de la composición de las feromonas y su uso para el seguimiento de plagas y el control mediante confusión sexual.

Estudio de la distribución espacial de Cydia pomonella (L.) y Pandemis heparana (Denis & Schiffermüller) en Torregrossa (Lleida) mediante métodos geoestadísticos

El estudio de la distribución espacial de una especie por me'todos geoestadísticos se realiza mediante el conocimiento de la función semivariograma. Después de calcular el semivariograma se procede a la estimación de la variable regionalizada en cualquier punto de la zona de estudio. Esta estimación se realiza mediante técnicas de interpolación lineal llamadas «krigeado», en honor a Krige y Matheron, fundadores de la geoestadística. El «krigeado» se basa en la minimización de la varianza del error en cada punto de estudio, previamente localizado en el espacio por sus coordenadas de situación. Cydia pomonella (L.) y Pandemis heparana (Denis & Schiffermüller) son dos tortrícidos plaga del manzano y del peral. La estimación de sus poblaciones se realiza mediante trampas de feromona y es posible disponer de una amplia base de datos. El objetivo de este trabajo fue analizar la idoneidad de los métodos geoestadísticos para el estudio de poblaciones de insectos y aplicarlas al caso concreto de C. pomonella y P. heparana. Se utilizaron las capturas en 55 estaciones con trampas de feromonas (difusor de origen Wageningen) colocadas en parcelas comerciales de manzano y peral en 1996 y 1997 en el término municipal de Torregrossa (Lleida). La idoneidad de los métodos geoestadísticos quedó demostrada por el hecho de que la variable número acumulado de machos por trampa fue regionalizable. Una vez calculadas las funciones semivariograma para cada especie y año, se han dibujado los mapas de distribución mediante el uso de isolíneas. En el futuro, se plantea la posibilidad de ampliar la zona de estudio a toda la zona frutera de Lleida y analizar la influencia de variables independientes (climáticas ...) sobre la distribución espacial mediante métodos de «co-krigeado».

Efecto de la amputación de antenas en machos y hembras, de la presencia de planta y de la concentración de feromona en el apareamiento de Sesamia nonagrioides Lef.

Se ha estudiado en laboratorio algunos de los factores que pueden influir en el apareamiento de los individuos de Sesamia nonagrioides Let'., como son la presencia de antenas en los individuos de ambos sexos, la presencia de plantas de maíz y la concentración de feromona sintética en el ambiente. Se ha visto que la amputación de antenas a las hembras no tiene ningún efecto sobre el porcentaje de apareamiento, mientras que la amputación de antenas a los machos lo reduce totalmente. La presencia de feromona sintética en el ambiente reduce significativamente el acoplamiento, siendo esta reducción mayor cuanto mayor es la dosis de feromona. En estos experimentos también se demuestra que cuanto mayor es la densidad de población menor es la reducción del acoplamiento. Finalmente, se ha observado que no hay diferencias de apareamiento con o sin plantas.

Utilización de análogos fluorados de la feromona sexual de Sesamia nonagrioides Lef. como inhibidores de su actividad biológica

Se ha estudiado el papel, como inhibidores de la acción feromonal, de determinados fluoroderivados, análogos estructurales del acetato de (Z)-l 1-hexadecenilo, componente principal de la feromona sexual del noctuido Sesamia nonagrioides Lef. Dichos compuestos fueron los análogos fluoroacetato (mono, di y trifluoroacetato de (Z)-l 1-hexadecenilo) y la trifluorometilcetona análoga [(Z)-1,1,1 -trifluoro-14-nonadecen-2-ona]. La acción inhibidora fue evaluada a partir de los resultados de actividad electrofisiológica (pruebas de electroantenograma, EAG), de estudios de comportamiento en pruebas de túnel de viento y de pruebas de capturas en campo. Los acetatos fluorados, especialmente el mono y el trifluoracetato, se mostraron como buenos inhibidores de la acción atrayente de la feromona en los tres tipos de pruebas realizadas, mientras que la trifluorometilcetona análoga mostró una actividad mucho menor.

Comparison of lures loaded with codlemone and pear ester for capturing codling moths, Cydia pomonella, in apple and pear orchards using mating disruption

Studies were conducted in apple, Malus domestica Borkhausen and pear, Pyrus communis L. (Rosales: Rosaceae), orchards to evaluate the attractiveness of grey halobutyl septa loaded with 1 (L2) and 10 (Mega) mg of codlemone, 8E,10E-dodecadien-1-ol, 3 mg of pear ester, ethyl (E,Z)- 2,4-decadienoate (DA2313), and 3 mg of pear ester plus 3 mg of codlemone (Combo) to adult codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae). All studies were conducted in orchards treated with pheromone mating disruption. All four lures were tested on diamond-shaped sticky traps placed in 60 plots of apple and 40 plots of pears in 2003/04, and in 62 plots of apples and 30 of pears in 2004-05. Combo lures attracted significantly more moths (males + females) than all the others in both years. Comparisons among flights showed significant differences mainly for flight 1 and 2, but not always for flight 3. Mega lures provided no significant improvement compared with L2 lures during both seasons regarding the total number of moths. Combo and DA2313 lures attracted fewer females than males during the whole season. For most sample dates, more virgin than mated females were attracted to Combo lures, except during the third flight, and the overall ratio was 60:40, although the difference was not statistically significant. We conclude that the Combo lures are better indicators of codling moth activity in pheromone treated orchards, regardless of pest population level, when compared with similar lures containing codlemone or pear ester alone.

Characterization of an antennal carboxylesterase from the pest moth Spodoptera littoralis degrading a host plant odorant.

Background: Carboxyl/cholinesterases (CCEs) are highly diversified in insects. These enzymes have a broad range of proposed functions, in neuro/developmental processes, dietary detoxification, insecticide resistance or hormone/pheromone degradation. As few functional data are available on purified or recombinant CCEs, the physiological role of most of these enzymes is unknown. Concerning their role in olfaction, only two CCEs able to metabolize sex pheromones have been functionally characterized in insects. These enzymes are only expressed in the male antennae, and secreted into the lumen of the pheromone-sensitive sensilla. CCEs able to hydrolyze other odorants than sex pheromones, such as plant volatiles, have not been identified. Methodology: In Spodoptera littoralis, a major crop pest, a diversity of antennal CCEs has been previously identified. We have employed here a combination of molecular biology, biochemistry and electrophysiology approaches to functionally characterize an intracellular CCE, SlCXE10, whose predominant expression in the olfactory sensilla suggested a role in olfaction. A recombinant protein was produced using the baculovirus system and we tested its catabolic properties towards a plant volatile and the sex pheromone components. Conclusion: We showed that SlCXE10 could efficiently hydrolyze a green leaf volatile and to a lesser extent the sex pheromone components. The transcript level in male antennae was also strongly induced by exposure to this plant odorant. In antennae, SlCXE10 expression was associated with sensilla responding to the sex pheromones and to plant odours. These results suggest that a CCE-based intracellular metabolism of odorants could occur in insect antennae, in addition to the extracellular metabolism occurring within the sensillar lumen. This is the first functional characterization of an Odorant- Degrading Enzyme active towards a host plant volatile.

Moths behaving like butterflies. Evolutionary loss of long range attractant pheromones in Castniid Moths: A Paysandisia archon model

Background: In the course of evolution butterflies and moths developed two different reproductive behaviors. Whereas butterflies rely on visual stimuli for mate location, moths use the"female calling plus male seduction" system, in which females release long-range sex pheromones to attract conspecific males. There are few exceptions from this pattern but in all cases known female moths possess sex pheromone glands which apparently have been lost in female butterflies. In the day-flying moth family Castniidae ("butterfly-moths"), which includes some important crop pests, no pheromones have been found so far. Methodology/Principal Findings: Using a multidisciplinary approach we described the steps involved in the courtship of P. archon, showing that visual cues are the only ones used for mate location; showed that the morphology and fine structure of the antennae of this moth are strikingly similar to those of butterflies, with male sensilla apparently not suited to detect female-released long range pheromones; showed that its females lack pheromone-producing glands, and identified three compounds as putative male sex pheromone (MSP) components of P. archon, released from the proximal halves of male forewings and hindwings. Conclusions/Significance: This study provides evidence for the first time in Lepidoptera that females of a moth do not produce any pheromone to attract males, and that mate location is achieved only visually by patrolling males, which may release a pheromone at short distance, putatively a mixture of Z,E-farnesal, E,E-farnesal, and (E,Z)-2,13-octadecadienol. The outlined behavior, long thought to be unique to butterflies, is likely to be widespread in Castniidae implying a novel, unparalleled butterfly-like reproductive behavior in moths. This will also have practical implications in applied entomology since it signifies that the monitoring/control of castniid pests should not be based on the use of female-produced pheromones, as it is usually done in many moths.

Dysregulation of apoptosis in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a major health problem, being the sixth most common cancer world-wide. Dysregulation of the balance between proliferation and cell death represents a pro-tumorigenic principle in human hepatocarcinogenesis. This review updates the recent relevant contributions reporting molecular alterations for HCC that induce an imbalance in the regulation of apoptosis. Alterations in the expression and/or activation of p53 are frequent in HCC cells, which confer on them resistance to chemotherapeutic drugs. Many HCCs are also insensitive to apoptosis induced either by death receptor ligands, such as FasL or TRAIL, or by transforming growth factor-beta (TGF-beta). Although the expression of some pro-apoptotic genes is decreased, the balance between death and survival is dysregulated in HCC mainly due to overactivation of anti-apoptotic pathways. Indeed, some molecules involved in counteracting apoptosis, such as Bcl-XL, Mcl-1, c-IAP1, XIAP or survivin are over-expressed in HCC cells. Furthermore, some growth factors that mediate cell survival are up-regulated in HCC, as well as the molecules involved in the machinery responsible for cleavage of their pro-forms to an active peptide. The expression and/or activation of the JAK/STAT, PI3K/AKT and RAS/ERKs pathways are enhanced in many HCC cells, conferring on them resistance to apoptotic stimuli. Finally, recent evidence indicates that inflammatory processes, as well as the epithelial-mesenchymal transitions that occur in HCC cells to facilitate their dissemination, are related to cell survival. Therefore, therapeutic strategies to selectively inhibit anti-apoptotic signals in liver tumor cells have the potential to provide powerful tools to treat HCC.

New sample of drosophilids from the Font Groga site, Barcelona (Spain)

A new sample of drosophilids was obtained from Font Groga (Barcelona) on 9th October 2013. Flies were netted over 12 baits containing fermenting bananas placed along a trail from 4 to 7 pm. The number of flies classified according to species and sex is presented in Table 1. The most abundant species is D. subobscura (62.60%). This is expected because the sample was obtained during its autumn peak of expansion. Also interesting is to find again D. suzukii, and in a percentage similar (9.20%) to that obtained in 2012 sample. This species invaded recently many European regions and seems it is well established. We have finally estimated the species diversity using H" (Shannon diversity index) and J (Shannon uniformity index). The values obtained were 0.990 and 0.615, respectively. They are similar to those estimates obtained in the same site by Calabria in autumn 2007 and higher than those of Canals et al. in late autumn 2012.